Effect pigments with high chroma and high brilliancy, method for the production and use thereof

ABSTRACT

The invention relates to an absorbent effect pigment including a nonmetallic substrate in platelet form and a coating applied thereto, wherein the coating includes at least one spacer layer. The invention further relates to a process for production of and to the use of the absorbent effect pigment.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is the national phase of PCT/EP2015/080862 filedDec. 21, 2015 and claims priority to European Patent Application No.14199126.5 filed Dec. 19, 2014, the entire disclosures of which arehereby incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to absorbent effect pigments comprising anonmetallic substrate in platelet form and a coating applied thereto,wherein the coating comprises at least one spacer layer, and to aprocess for production and to the use thereof.

Description of Related Art

Multilayer pigments which, based on a nonmetallic substrate in plateletform, comprise at least one layer sequence composed of layers ofalternately high, low and high refractive index are known, for example,from EP 1 572 812 A1, EP 1 213 330 A1, EP 1 025 168 B2, EP 1 621 585 A2,EP 0 948 572 A1, EP 0 950 693 A1, EP 1 306 412 A1, EP 1 587 881 A2, EP 2632 988 A1 or EP 1 474 486 A2. Depending on the optical layer thicknessof the layer of low refractive index, it is possible for the multilayerpigments to change their visual appearance depending on the viewingangle, as described, for example, in EP 1 375 601 A1, EP 1 281 732 A1,EP 0 753 545 A2, US 2004/0003758 A1. A common factor in all theapplications cited above is that the layer sequence includes a layer oflow refractive index composed of a metal oxide of low refractive index,for example silicon oxide.

Compared to monolayer effect pigments with just a single identical firstlayer, multilayer pigments feature higher gloss and in some cases higherchroma, naturally assuming that the substrate and particle size here arethe same.

EP 1 029 900 A1 discloses pigments which have been coated with (A) apseudobrookite coating of high refractive index, consisting of a mixtureof TiO₂ and Fe₂O₃ in a ratio of 10:1 to 1:3 and optionally one or moremetal oxides in amounts of ≤20% by weight, based on the layer (A), (B) acolorless coating having a refractive index n≤1.8, and optionally anouter protective layer. The application does not contain any pointer toa spacer layer within or between layers (A) and (B).

EP 1 230 308 A1 discloses pigments including at least two layersequences of (A) a colorless coating having a refractive index n≤1.8,(B) a coating of high refractive index composed of pseudobrookiteconsisting of a mixture of TiO₂ and Fe₂O₃ in a ratio of 1:0.1 to 1:5 andoptionally one or more metal oxides in amounts of 20% by weight, basedon the layer (B), and optionally (C) an outer protective layer. EP 1 230308 A1 does not give any pointer to a spacer layer within or betweenlayers (A) and (B).

EP 1 230 310 A1 discloses pigments comprising a layer sequence composedof (A) a coating of high refractive index, consisting of a mixture ofTiO₂ and Fe₂O₃ in a ratio of 1:0.1 to 1:5 and optionally one or moremetal oxides in amounts of ≤20% by weight, based on the layer (A), (B) acolorless coating having a refractive index n≤1.8, (C) a colorlesscoating having a refractive index n>1.8, (D) an absorbent coating havinga refractive index n>1.8, and optionally (E) an outer protective layer.There is no description of a spacer layer within or between theaforementioned layers in EP 1 230 310 A1.

WO 2014/094993 A1 discloses interference pigments based on multiplycoated substrates in platelet form which have, on the surface of thesubstrate, a layer sequence composed of (AO) optionally a layer composedof TiO₂, (A) a coating consisting of a mixture of TiO₂ and Fe₂O₃ whichmay optionally have been doped with one or more further oxides, (B) alayer composed of SnO₂, (C) a coating of high refractive index thatabsorbs in the visible wavelength range and optionally (D) an outerprotective layer. In layer (A) and/or (C) the mixing ratio of TiO₂ toFe₂O₃ is preferably 10:1 to 1:3. To increase the color intensity of thelayer (A) and/or the layer (C), it is also possible to mix one or moreoxides, for example Al₂O₃, Ce₂O₃, B₂O₃, ZrO₂, SnO₂, into the TiO₂/Fe₂O₃mixture. WO 2014/094993 A1 does not disclose a spacer layer within orbetween the above-described layers.

CN 101289580 A describes the production of golden pigments having astrong interference color, the pigments being said to have theappearance of 24K gold. In this case, a mica substrate is suspended inwater and a solution of TiCl₄ is added for coverage with a first layer,a solution of FeCl₃ and TiCl₄ for coverage with a second layer, asolution of SnO₂ for coverage with a third layer, and a solution ofTiCl₄ for coverage with a fourth layer. After filtration and washing,the pigment is dried at 120° C. to 200° C. and calcined at 820° C. CN101289580 A does not contain any pointer to a spacer layer in thecoating.

EP 1 422 268 A2 discloses a pigment with multilayer structure, saidpigment having two or more metal oxide layers, wherein the at least onemetal (ion) of the metal oxide layer is selected from the groupconsisting of cerium, tin, titanium, iron, zinc and zirconium. The aimof this application is pigments having high chroma and high brilliance,and having a minimum number of pores of minimum size in their coating.According to EP 1 422 268 A2, a low pore volume is said to assure acoating of high visual quality.

US 2015/0344677 A1 relates to effect pigments based on coated substratesin platelet form. The coating comprises first and second layers of highrefractive index, and a third component which is intended to diffusepartly or to an extent of 100% into one or both of the layers of highrefractive index. The third component may be SiO₂ or another metaloxide. The aim of this application, in the case of effect pigmentshaving a D₅₀ of 15 μm or less, is to obtain coverage with SiO₂ withoutagglomeration.

SUMMARY OF THE INVENTION

In some examples, there is provided an absorbent effect pigmentcomprising a nonmetallic substrate in platelet form and a coatingapplied to the substrate, wherein the coating comprises a) optionally alayer 1 comprising or consisting of at least one of tin oxide, tinhydroxide or tin oxide hydrate, b) a layer 2 comprising at least one ofmetal oxide, metal hydroxide or metal oxide hydrate, and c) a layer 3comprising at least one of metal oxide, metal hydroxide or metal oxidehydrate, at least one of layers 2 and 3 comprises at least two differentmetal ions and layers 2 and 3 are interrupted by a spacer layer.

Also provided are processes for producing the absorbent effect pigment.Articles comprising at least one absorbent effect pigment of the presentinvention also are provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description,will be better understood when read in conjunction with the appendeddrawings. In the drawings:

FIG. 1 is a scanning electron micrograph of a transverse section of aneffect pigment of the invention in 50,000-fold magnification (based onPolaroid 545);

FIG. 2 is a scanning electron micrograph of a transverse section of aneffect pigment of the invention in 50,000-fold magnification (based onPolaroid 545);

FIG. 3 is a scanning electron micrograph of a transverse section of aneffect pigment of the invention in 20,000-fold magnification (based onPolaroid 545);

FIG. 4 is a detail of the scanning electron micrograph of a transversesection from FIG. 2 with a baseline drawn in at the interface ofnonmetallic substrate in platelet form—coating, and lines arranged atright angles to the baseline. “x” marks the points of intersection atthe interfaces;

FIG. 5 is a scanning electron micrograph of a transverse section of thetitanium dioxide-coated pearlescent pigment SYMIC C261 (from ECKARTGmbH) in 20,000-fold magnification (based on Polaroid 545);

FIG. 6 is a schematic diagram of the spacer layer;

FIG. 7 is a schematic diagram of the position of the spacer layer;

FIG. 8 is a concentration profile (line scan) using a transverse sectionin a scanning electron microscope with energy-dispersive microanalyzer(EDX) of example 12 prior to calcination; and

FIG. 9 is a concentration profile (line scan) using a transverse sectionin a scanning electron microscope with energy-dispersive microanalyzer(EDX) of example 12 after calcination.

DETAILED DESCRIPTION

It was an object of the present invention to provide a high-chromapigment having high gloss and high hiding power, which has highmechanical stability and high chemical stability and is simultaneouslyproducible with low material input in a simple manner.

This object is achieved by providing an absorbent effect pigmentcomprising a nonmetallic substrate in platelet form and a coatingapplied to the substrate, wherein the coating includes

a) optionally a layer 1 comprising or consisting of tin oxide, tinhydroxide and/or tin oxide hydrate,

a) a layer 2 comprising at least one metal oxide, metal hydroxide and/ormetal oxide hydrate,

b) a layer 3 comprising at least one metal oxide, metal hydroxide and/ormetal oxide hydrate,

at least one of layers 2 and 3 comprises at least two different metalions and layers 2 and 3 are interrupted by a spacer layer.

What is meant by “interrupted” in accordance with the invention is thatlayers 2 and 3 are spaced apart or kept at a distance from one anotherby a spacer layer.

What is meant by the general expression “metal oxide, metal hydroxideand/or metal oxide hydrate” in accordance with the invention is “metaloxide and/or metal hydroxide and/or metal oxide hydrate”. This is alsotrue when the metal or metal ion is specified, for example as titanium(ion), iron (ion), tin (ion), zirconium (ion) etc.

What is meant by the expression “a metal ion” or “an iron ion” inaccordance with the invention is not one single metal ion or iron ion,but a multitude of metal ions or iron ions.

In a preferred embodiment, the optional layer 1 directly adjoins thenonmetallic substrate in platelet form, layer 2 directly follows layer 1and layer 3 follows layer 2, with layers 2 and 3 interrupted by a spacerlayer.

In a further embodiment, layer 2 directly adjoins the nonmetallicsubstrate in platelet form and layer 3 follows layer 2, with layers 2and 3 interrupted by a spacer layer.

Preferred developments of the absorbent effect pigment are specified independent claims 2 to 9.

The object is additionally achieved by provision of a process forproducing the absorbent effect pigment of the invention, wherein theprocess comprises the following steps:

-   (i) optionally applying an uncalcined layer comprising or consisting    of tin oxide, tin hydroxide and/or tin oxide hydrate to the    nonmetallic substrate in platelet form,-   (ii) sequentially applying three uncalcined layers A, B and C each    consisting of or comprising at least one metal oxide, metal    hydroxide and/or metal oxide hydrate, where the layers A, B and C    are arranged directly one on top of another and where the at least    one metal oxide, metal hydroxide and/or metal oxide hydrate applied    in the layer B, in relation to the metal ion, is different than the    metal ion(s) of the metal oxides, metal hydroxides and/or metal    oxide hydrates of layer A and layer C,-   (iii) calcining the product obtained in step (ii) at a temperature    from a range from 600° C. to 1000° C. to obtain the absorbent effect    pigment comprising at least one spacer layer.

The object is alternatively achieved by provision of a process forproducing the absorbent effect pigment of the invention, wherein theprocess comprises the following steps:

-   (i) sequentially applying two uncalcined layers B and C each    consisting of or comprising at least one metal oxide, metal    hydroxide and/or metal oxide hydrate to a calcined, singly or    multiply coated nonmetallic substrate, where the layers B and C are    arranged directly one on top of another and where the at least one    metal oxide, metal hydroxide and/or metal oxide hydrate applied in    the layer B, in relation to the metal ion, is different than the    metal ion(s) of the metal oxide, metal hydroxide and/or metal oxide    hydrate of layer C and of the layer which directly adjoins layer B    in the substrate direction,-   (ii) calcining the product obtained in step (i) at a temperature    from a range from 600° C. to 1000° C. to obtain the absorbent effect    pigment comprising at least one spacer layer.

The invention further provides for the use of the absorbent effectpigment of the invention in cosmetic formulations, plastics, films,textiles, ceramic materials, glasses, paints, printing inks, writinginks, varnishes, powder coatings and/or in functional applications, forexample for laser marking, IR reflection, photocatalysis.

The object underlying the invention is additionally achieved byprovision of an article, wherein the article includes at least oneabsorbent effect pigment of the invention.

The nonmetallic substrates in platelet form that are to be coated may beselected from the group consisting of natural mica platelets, syntheticmica platelets, iron mica platelets, glass platelets, iron oxideplatelets, SiO₂ platelets, Al₂O₃ platelets, kaolin platelets, talcplatelets and bismuth oxychloride platelets. According to the invention,the absorbent effect pigments may also be based on mixtures of theabove-specified nonmetallic substrates in platelet form. Theaforementioned nonmetallic substrates in platelet form may also includeone or more layers composed of or comprising at least one metal oxide,metal hydroxide and/or metal oxide hydrate of high and/or low refractiveindex. For instance, the substrates used may thus also be singly ormultiply coated pearlescent pigments or interference pigments. In apreferred embodiment, the substrates to be used in accordance with theinvention are uncoated nonmetallic substrates in platelet form.

The nonmetallic substrates in platelet form are preferably selected fromthe group consisting of natural mica platelets, synthetic micaplatelets, glass platelets, SiO₂ platelets, Al₂O₃ platelets and mixturesthereof. The nonmetallic substrates in platelet form are more preferablyselected from the group consisting of natural mica platelets, syntheticmica platelets, glass platelets and mixtures thereof. Very particularlypreferred nonmetallic substrates in platelet form are synthetic micaplatelets and/or glass platelets and mixtures thereof. Especially glassplatelets are preferred as nonmetallic substrate in platelet form.

The glass platelets usable as substrate may, with regard to theircomposition, consist of silicate glass, such as soda-lime glass, leadcrystal glass, E glass, A glass, C glass, ECR glass, Duran glass, windowglass, laboratory glass, aluminosilicate glass or borosilicate glass.Preferably, the glass platelets have a composition corresponding to theteaching, especially corresponding to the main claim, of EP 1 980 594B1, more preferably corresponding to the teaching, especially accordingto the respective main claims, of EP 1 829 833 B1 or EP 2 042 474 B1.The glass platelets usable as substrate are preferably produced by theprocess described in EP 289 240 B1.

In a further embodiment, the glass platelets can be colored in acontrolled manner in the course of their production by the addition ofat least one inorganic colorant. Suitable colorants are those that donot break down at the particular melting temperature of the glasscomposition. The proportion of colorant here is preferably within arange from 0.1% by weight to 50% by weight in total, more preferablywithin a range from 1% by weight to 35% by weight in total and mostpreferably within a range from 5% by weight to 25% by weight in total,based in each case on the total weight of the glass composition.Suitable colorants are especially elemental noble metals, such as Au, Pdor Pt, the cations or complex anions of the elements Cu, Cr, Mn, Fe, Tiand/or Co, and mixtures of the colorants listed above.

In a further embodiment, the refractive index of the glass plateletsusable as substrate is within a range from 1.45 to 1.80, preferablywithin a range from 1.50 to 1.70.

In a further embodiment, the substrates in platelet form, especiallyglass platelets, may be ensheathed by a layer comprising or consistingof silicon oxide, silicon hydroxide, silicon oxide hydrate. For example,the aforementioned coating, in the case of use of glass platelets, canprotect the glass surface from chemical alteration, such as swelling,leaching of glass constituents or dissolution in aggressive acidiccoverage solutions.

The synthetic mica platelets usable as substrate may have a compositionaccording to the main claim of CN 102718229 A or according to the mainclaim of US 2014/0251184 A1. They may additionally be produced accordingto the details in EP 0 723 997 A1, page 3 to page 4.

The synthetic mica platelets usable as substrate are preferablyfluorphlogopite of the formula KMg₃AlSi₃O₁₀F₂, KMg₂½(Si₄O₁₀)F₂ orNaMg₂½(Si₄O₁₀) F₂, especially fluorphlogopite of the formulaKMg₃AlSi₃O₁₀F₂, which, according to x-ray fluorescence analysis (XRF),preferably has the constituents specified in table 1 as the respectivemetal oxide within the ranges listed therein.

TABLE 1 Preferred compositions of synthetic mica platelets according toXRF Composition of synthetic mica platelets, figures in % by weight,based in each case on the total weight of the synthetic mica plateletsSiO₂ 38 to 46 Al₂O₃ 10 to 14 K₂O 9 to 13 Fe₂O₃ 0.01 to 0.25 MgO 26 to 34MnO 0 to 0.05 Na₂O 0 to 13

The mean thickness of the nonmetallic substrates in platelet form thatare to be coated is preferably within a range from 50 nm to 5000 nm,more preferably within a range from 60 nm to 3000 nm and most preferablywithin a range from 70 nm to 2000 nm. The mean thickness is understoodin accordance with the invention to mean the arithmetic mean, unlessstated otherwise.

In one embodiment, the mean thickness for glass platelets as thenonmetallic substrate in platelet form that is to be coated is within arange from 750 nm to 1500 nm, preferably within a range from 850 nm to1400 nm and more preferably within a range from 900 nm to 1300 nm.

Thinner substrates in platelet form lead to a lower overall thickness ofthe absorbent effect pigments of the invention. Thus, likewise preferredas nonmetallic substrate in platelet form are glass platelets whereinthe mean thickness is within a range from 50 nm to 700 nm, furtherpreferably within a range from 101 nm to 600 nm, more preferably withina range from 160 nm to 500 nm and most preferably within a range from200 nm to 400 nm.

In a further embodiment, the mean thickness of the natural or syntheticmica platelets as the nonmetallic substrate in platelet form that is tobe coated is preferably within a range from 80 nm to 1300 nm, furtherpreferably within a range from 90 nm to 1000 nm, more preferably withina range from 99 nm to 800 nm and most preferably within a range from 200nm to 600 nm.

If nonmetallic substrates in platelet form are coated below a meanthickness of 50 nm with metal oxides of high refractive index, forexample, extremely fracture-sensitive pigments are obtained, which canbreak up even on incorporation into the respective application medium,which in turn results in significant lowering of the gloss.

Above a mean substrate thickness of 5000 nm, the pigments can become toothick overall. This is associated with a poorer specific hidingcapacity, meaning that the area covered per unit weight of absorbenteffect pigment of the invention is lower. Moreover, such thick pigmentshave a lower degree of plane-parallel orientation to the substrate inthe application medium. Poorer orientation in turn results in reducedgloss. With regard to tactile properties too, excessively thick effectpigments can be disadvantageous in an application.

In one embodiment, the relative standard deviation in the thicknessdistribution of the nonmetallic substrates in platelet form is 15% to100%, preferably 17% to 70%, more preferably 19% to 61% and mostpreferably 21% to 41%. The relative standard deviation in [%] is thequotient of calculated standard deviation and mean thickness.

The mean thickness of the nonmetallic substrate in platelet form isdetermined, using a cured lacquer film in which the absorbent effectpigments of the invention are aligned essentially plane-parallel to thesubstrate, according to the details below in section Ilk “Determinationof the mean thickness of the nonmetallic substrates in platelet form,the mean layer thickness of layers 2 and 3, the mean layer thickness ofthe overall coating, the mean height h_(a) of the spacer layer and themean height h_(H) of the cavities”. For this purpose, a transversesection of the cured lacquer film is examined under a scanning electronmicroscope (SEM), wherein the thickness of the nonmetallic substrate inplatelet form is determined for at least 100 effect pigments andstatistically averaged. According to the invention, the term “mean”always means the arithmetic mean, unless stated otherwise.

The scanning electron micrographs were obtained using transversesections of the absorbent effect pigments of the invention with theSupra 35 scanning electron microscope (from Zeiss).

The absorbent effect pigments of the invention optionally comprise alayer 1 comprising or consisting of tin oxide, tin hydroxide and/or tinoxide hydrate. Layer 1 may optionally be present at least partly as amixed layer with a layer directly adjoining layer 1, for example layer2.

Layers 2 and 3 of the absorbent effect pigments of the invention, aftercalcination, are preferably each a layer of high refractive index,wherein the refractive index is preferably n>1.8, more preferably n≥1.9and most preferably n≥2.1. According to the invention, the selection ofthe at least two different metal ions in layers 2 and 3 is made suchthat the metal oxide(s), metal hydroxide(s) and/or metal oxidehydrate(s) that form therefrom in layers 2 and/or 3 preferably each hasor have an averaged refractive index of n>1.8.

The at least one metal oxide, metal hydroxide and/or metal oxide hydrateof layers 2 and 3 comprises at least two different metal ions,preferably selected from the group of metals consisting of Ti, Fe, Sn,Mn, Zr, Ca, Sr, Ba, Ni, Sb, Ag, Zn, Cu, Ce, Cr and Co, furtherpreferably selected from the group of metals consisting of Ti, Fe, Sn,Mn, Zr, Ag, Zn, Cu and Ce, further preferably selected from the group ofmetals consisting of Ti, Fe, Sn, Ag, Zr and Ce, more preferably selectedfrom the group of metals consisting of Fe, Sn, Ag, Zr and Ce, and mostpreferably selected from the group of metals consisting of Zr, Fe andSn. According to the invention, the selection of the at least twodifferent metal ions is made such that the resulting effect pigments ofthe invention are absorbent. “Absorbent effect pigments” is understoodin the context of this invention to mean that the hiding quotientthereof, D_(q), defined as

${D_{q} = \frac{L_{black}^{*25}}{L_{white}^{*25}}},$is ≥0.41, preferably ≥0.45, more preferably ≥0.50 and most preferably≥0.55. The hiding quotient is determined here using lacquerapplications, on black/white hiding charts (Byko-Chart 2853, fromByk-Gardner), of a nitrocellulose lacquer (Erco 2615e bronze mixinglacquer colorless; from Maeder Plastiklack AG) which has been admixedwith 6% by weight of the particular effect pigment of the invention,according to the details which follow in section IIc “Comparison ofhiding”. L*²⁵ _(black) and L*²⁵ _(white) here are the brightness valuesmeasured at a measurement angle of 25° on black and white backgrounds ofthe black/white hiding charts, preferably with the BYK-mac multi-anglecolorimeter from Byk-Gardner.

The proportion of noncoloring metal ions selected from the group ofmetals consisting of Ti, Sn, Zr, Ca, Sr, Ba and Zn preferably totals 40%by weight, the proportion of noncoloring metal ions being morepreferably within a range from 0.1% by weight to 35% by weight in totaland more preferably within a range from 1% by weight to 24% by weight intotal, and the proportion of coloring metal ions selected from the groupof metals consisting of Fe, Ti, Sn, Mn, Ni, Sb, Ag, Cu, Ce, Cr and Copreferably totals 4% by weight, the proportion of coloring metal ionsbeing more preferably within a range from 5% by weight to 80% by weightin total and most preferably within a range from 20% by weight to 72% byweight in total, determined by means of XRF in each case, calculated ineach case as the elemental metal and based in each case on the totalweight of the absorbent effect pigment of the invention. The weightratio of noncoloring metal ions to coloring metal ions in the absorbenteffect pigment of the invention here is preferably <20, furtherpreferably <10, more preferably <1 and most preferably <0.8.

Coloring metal ions from the group of the metals Ti and Sn relateespecially to Ti in the +3 or +2 oxidation state and Sn in the +2oxidation state.

The at least two different metal ions are preferably present either inhomogeneous distribution in layers 2 and/or 3 or form a gradienttherein. In exceptional cases, the at least two different metal ions mayalso be present in inhomogeneous distribution in layers 2 and/or 3.

What is meant by “at least two different metal ions” in accordance withthe invention is that at least two metal ions of different elements arepresent, for example titanium and iron ions, or titanium and tin ions,or titanium and zirconium ions, or iron and tin ions, or iron andzirconium ions, etc. The various metal ions may be present in layer 2and/or layer 3 of the absorbent effect pigment of the invention in amixture of metal oxides and/or metal hydroxides and/or metal oxidehydrates and/or else in mixed oxides and/or mixed hydroxides and/ormixed oxide hydrates. Layer 2 and/or layer 3 may comprise or consist ofthis mixture of metal oxides and/or metal hydroxides and/or metal oxidehydrates and/or mixed oxides and/or mixed hydroxides and/or mixed oxidehydrates.

Preferably, in accordance with the invention, in the case of use of themetal ions Ti and Fe, the component comprising iron ions in therespective layer is present in layer 2 and/or in layer 3 in the calcinedabsorbent effect pigment of the invention in the form of iron titanate,preferably in the form of pseudobrookite and/or pseudorutile.

In one embodiment, one of the two layers 2 and 3 comprises only one kindof metal ion, preferably selected from the group of metals consisting ofFe, Ti, Sn and Zr, more preferably consisting of Fe, Ti and Sn.Correspondingly, the respective other layer of the two layers 3 and 2includes at least two different metal ions, preferably selected from thegroup of metals consisting of Ti, Sn, Zr and Fe, further preferablyconsisting of Ti, Sn and Fe.

In a preferred embodiment, both layer 2 and layer 3 comprise at leastone metal oxide, metal hydroxide and/or metal oxide hydrate composed ofor comprising at least two metal ions selected from the group of metalsconsisting of Ti, Sn, Zr and Fe, further preferably consisting of Ti, Snand Fe.

In a further embodiment, the layers 2 and 3 interrupted by the spacerlayer are virtually identical in respect of the particular composition.

If the absorbent effect pigments of the invention comprise at least onecoloring metal ion selected from the group of metals consisting of Fe,Ti, Sn, Mn, Cu, Cr, Co, Ag and Ce, the proportion thereof, determined ineach case by means of XRF and calculated in each case as the elementalmetal, preferably totals ≥4% by weight, and is further preferably withina range from 6% by weight to 85% by weight in total, more preferablywithin a range from 8% by weight to 79% by weight in total and mostpreferably within a range from 10% by weight to 76% by weight in total,based in each case on the total weight of the absorbent effect pigment.

In a preferred embodiment, at least one of layers 2 and 3 comprises atleast two different metal ions selected from the group of metalsconsisting of Ti, Fe, Sn, Mn, Zr, Ca, Sr, Ba, Ni, Sb, Ag, Zn, Cu, Ce, Crand Co, where at least one of these two metal ions is selected from thegroup of metals consisting of Ti, Sn, Zr and Zn and where the proportionof coloring metal ions selected from the group of metals consisting ofFe, Ti, Sn, Mn, Cu, Cr, Co, Ag and Ce, determined in each case by meansof XRF and calculated in each case as the elemental metal, preferablytotals >4% by weight, based on the total weight of the absorbent effectpigment of the invention.

In a particularly preferred embodiment, at least one of layers 2 and 3comprises metal oxides, metal hydroxides and/or metal oxide hydrates,where the metal ions of the metal oxides, metal hydroxides and/or metaloxide hydrates comprise or are the metals Ti and Fe, where the weightratio of Ti to Fe, determined in each case by means of XRF andcalculated in each case as the elemental metal, is <15, preferably <10,more preferably <5 and most preferably <1, and where the proportion ofFe, determined by means of XRF and calculated as the elemental metal, ispreferably >4% by weight, based on the total weight of the absorbenteffect pigment of the invention.

In a further particularly preferred embodiment, at least one of layers 2and 3 comprises metal oxides, metal hydroxides and/or metal oxidehydrates, where the metal ions of the metal oxides, metal hydroxidesand/or metal oxide hydrates comprise or are the metals Fe and Sn, wherethe weight ratio of Fe to Sn, determined in each case by means of XRFand calculated in each case as the elemental metal, is preferably from arange from 1 to 80, further preferably from a range from 2 to 60, morepreferably from a range from 3 to 50 and most preferably from a rangefrom 4 to 40, and where the proportion of Sn, determined by means of XRFand calculated as the elemental metal, is preferably selected from arange from 1% by weight to 25% by weight, further preferably from arange from 2% by weight to 19% by weight and more preferably from arange from 4% by weight to 15% by weight, based in each case on thetotal weight of the absorbent effect pigment of the invention.

In a further particularly preferred embodiment, at least one of layers 2and 3 comprises metal oxides, metal hydroxides and/or metal oxidehydrates, where the metal ions of the metal oxides, metal hydroxidesand/or metal oxide hydrates comprise or are the metals Fe and Zr, wherethe weight ratio of Fe to Zr, determined in each case by means of XRFand calculated in each case as the elemental metal, is selected from arange from 1 to 75, preferably from a range from 2 to 65, morepreferably from a range from 4 to 48 and most preferably from a rangefrom 8 to 36, based in each case on the total weight of the absorbenteffect pigment of the invention.

The metal oxide, metal hydroxide and/or metal oxide hydrate contents ofthe absorbent effect pigments of the invention are determined as therespective metal oxide by means of x-ray fluorescence analysis (XRF) andcan be calculated as the respective elemental metal. For this purpose,the absorbent effect pigment is incorporated into a lithium tetraborateglass tablet, fixed in solid sample measuring cups and analyzedtherefrom. The measuring instrument used was the Advantix ARL systemfrom Thermo Scientific.

The mean layer thickness of layer 1 is preferably less than 10 nm, morepreferably less than 5 nm and most preferably less than 3 nm, with layer1 completely ensheathing or incompletely ensheathing the nonmetallicsubstrate in platelet form or an optionally present coating.

The mean layer thickness of each of layers 2 and 3 of the absorbenteffect pigments of the invention is preferably within a range from 30 nmto 350 nm, further preferably within a range from 35 nm to 310 nm,further preferably within a range from 90 nm to 340 nm, more preferablywithin a range from 40 nm to 280 nm and most preferably within a rangefrom 50 nm to 210 nm.

In a preferred embodiment, the mean layer thickness of layers 2 and 3 isvirtually the same. What is understood by “virtually the same mean layerthickness” in accordance with the invention is that the quotient of themean layer thickness of layer 2 and the mean layer thickness of layer 3is preferably within a range from 0.5 to 1.8, further preferably withina range from 0.7 to 1.6, more preferably within a range from 0.8 to 1.4and most preferably within a range from 0.9 to 1.2.

In a further embodiment, in the case of a different physical compositionof layers 2 and 3, the respective optical layer thickness thereof isvirtually the same, where the optical layer thickness of layers 2 and 3may or may not follow the known lambda/4 rule. The optical layerthickness is defined as the product of refractive index and mean layerthickness of the respective layer.

The mean layer thickness of the overall coating of the absorbent effectpigments of the invention is preferably ≤800 nm. The mean layerthickness of the overall coating is preferably within a range from 45 nmto 650 nm, more preferably within a range from 65 nm to 530 nm and mostpreferably within a range from 80 nm to 380 nm.

“Overall coating” is understood to mean the complete coating whichproceeds from the substrate surface and extends perpendicularlytherefrom in one direction.

In one embodiment, the relative standard deviation of the layerthickness distribution of layers 2 and 3 is 2% to 74%, preferably 3% to63%, more preferably 4% to 57% and most preferably 5% to 49%, and therelative standard deviation of the layer thickness distribution of theoverall coating is 0.3% to 31%, preferably 1% to 27%, more preferably1.2% to 24% and most preferably 1.9% to 22%. The relative standarddeviation in [%] is the quotient of calculated standard deviation andmean thickness.

The spacer layer between layers 2 and 3 is preferably arrangedessentially parallel to the surface of the nonmetallic substrate inplatelet form. What is understood by “essentially parallel” in thecontext of this invention is that, in a scanning electron micrograph ofa transverse section, a regression line drawn through a spacer layer, inrelation to a regression line drawn on the surface of the nonmetallicsubstrate in platelet form, has a slope of preferably close to 0.

The position of the spacer layer within the overall coating may vary.If, for example, the mean layer thicknesses of layers 2 and 3 arevirtually identical, the spacer layer, in relation to the overallcoating, preferably composed of optional layer 1 and layers 2 and 3, isin about the middle of the overall coating, since the optional layer 1is preferably extremely thin, more preferably just a few atom layersthick. The spacer layer is preferably arranged between the first sixthand the sixth sixth of the overall coating in relation to the overallcoating. The first sixth here refers to the proportion facing thenonmetallic substrate in platelet form, and the sixth sixth to theproportion of the overall coating remote from the nonmetallic substratein platelet form (FIG. 7).

The spacer layer formed between layers 2 and 3 preferably hasconnections, which can also be referred to as spacers, which on the onehand connect the layers adjoining on either side of the spacer layer andon the other hand keep them spaced apart. As apparent from scanningelectron micrographs of transverse sections, these connections orspacers, for example in the form of bars or columns, may be arranged atan angle of about 90°, for example of 80° to 100°, to the surface of thenonmetallic substrate in platelet form. However, they may also assumeany other angle between 5° and 175°. Preferably, the spacers, especiallybars, preferably the longitudinal axes of the spacers, preferably bars,are arranged at an angle from a range from 15° to 150° and morepreferably at an angle from a range from 35° to 135°, in each case tothe surface of the nonmetallic substrate in platelet form. In thedetermination of the angle, the substrate plane forms the first limb.One of the outsides of the bar in question in each case forms the secondlimb. The angle formed is determined proceeding from the angle vertex ofthe two limbs, with 0° being assumed to lie to the left and 180° to theright in the substrate plane in the top view of the scanning electronmicrographs of transverse sections.

The connections or spacers may assume various geometric forms and arepreferably distributed homogeneously over the entire spacer layer. Forexample, the connections or spacers may take the form of meshes, grids,ladders, sponges or honeycombs. It may also be possible to identify somestructural elements similar to those in a photonic or inverse photoniccrystal, as known, for example, from EP 2 371 908 A2, EP 1 546 063 A1 orEP 1 121 334 A1.

The connections or spacers comprise at least one metal oxide, metalhydroxide and/or metal oxide hydrate. In a preferred embodiment, theconnections or spacers comprise an identical physical composition to thelayers on either side of the spacer layer. It is also alternativelypossible for a gradient between various metal oxides, metal hydroxidesand/or metal oxide hydrates to be formed within the connections orspacers.

In a preferred embodiment, the connections or spacers comprise a metaloxide, metal hydroxide and/or metal oxide hydrate, where the metal ionsof the metal oxides, metal hydroxides and/or metal oxide hydratescomprise or are at least two metal ions selected from the group ofmetals consisting of Ti, Fe, Sn, Mn, Zr, Ca, Sr, Ba, Ni, Ag, Zn, Cu, Ce,Cr and Co, further preferably from the group consisting of Ti, Fe, Sn,Mn, Zr, Ag, Zn, Cu and Ce, more preferably from the group consisting ofTi, Fe, Sn, Zr, Ag and Ce, and most preferably from the group consistingof Ti, Fe and Sn.

The inventors assume that the connections or spacers can also bringabout mechanical stabilization of the adjoining layers and hence of theabsorbent effect pigment of the invention. Probably because of thenumber of connections or spacers, the different angles and geometricforms that the compounds or spacers can assume within the spacer layer,and the distribution thereof in a preferably homogeneous manner over thefull area of the spacer layer, a mechanically very stable effect pigmentis formed. The adhesion between the overall coating and the nonmetallicsubstrate in platelet form is very good in the absorbent effect pigmentsof the invention. Even extreme shear conditions as occur in what iscalled the Waring blender test are withstood by the absorbent effectpigments of the invention without detectable damage. The procedure ofthe Waring blender test is described hereinafter in section IIf “Waringblender test”.

As well as their surprisingly good mechanical stability, the absorbenteffect pigments of the invention have excellent chemical stability, aselucidated in the details below in section IIg “Determination ofchemical stability”.

The spacer layer of the absorbent effect pigments of the inventionpreferably has a mean height h_(a) from a range from 5 nm to 120 nm,further preferably from a range from 9 nm to 95 nm, further preferablyfrom a range from 16 nm to 76 nm, further preferably from a range from21 nm to 69 nm, more preferably from a range from 22 nm to 62 nm andmost preferably from a range from 26 nm to 56 nm (FIG. 6).

To determine the mean height h_(a) of the spacer layer, the mean layerthickness of layers 2 and 3 and the mean layer thickness of the overallcoating, scanning electron micrographs of transverse sections are usedto establish the upper and lower substrate surfaces as baselines. Whatis meant by the upper and lower substrate surfaces in the scanningelectron micrographs of transverse sections is the longer side of thenonmetallic substrate in platelet form in each case. The baseline isdrawn onto the scanning electron micrograph of the transverse sectionalong the surface of the nonmetallic substrate in platelet form. Thescanning electron micrographs of transverse sections were analyzed withthe aid of the AxioVision 4.6.3 image processing software (from Zeiss).

A sufficient number of parallel lines are drawn at 50 nm intervals at a90° angle from these two baselines as to place a grid over the effectpigment shown in the scanning electron micrograph of the transversesection (FIG. 4). The magnification of the scanning electron micrographof the transverse section is preferably at least 50 000-fold, based onPolaroid 545 (4″×5″). Proceeding from the respective baseline of thenonmetallic substrate in platelet form, in the direction of therespective outer layer 3 or the respective outermost layer, the pointsof intersection between the parallel lines arranged at right angles tothe respective baseline with the respective interfaces of the optionallayer 1 with layer 2, of layer 2 with the spacer layer, of the spacerlayer with layer 3, and of layer 3 with the environment or with anyfurther layer applied are analyzed manually. It may be the case herethat one of the lines drawn at 50 nm intervals occurs directly above aconnection point or a spacer. In this case, only the respective point ofintersection at the interface of layer 3 with the environment or withany further layer applied is recorded.

These measurements give rise to the layer thicknesses of layers 2 and 3,the layer thickness of the overall coating, the layer thickness offurther layers optionally present, and the height h_(a) of the spacerlayer by formation of differences. The layer thickness of layer 2 iscalculated from the difference between the respective measured points ofintersection at the respective interfaces of layer 2 with the spacerlayer and of either optional layer 1 with layer 2 or the baseline withlayer 2 if the nonmetallic substrate in platelet form has not beencovered with further layers beforehand. The layer thickness of layer 3is calculated from the difference between the respective measured pointsof intersection of layer 3 with the environment or any further layerapplied and of the spacer layer with layer 3. The layer thickness of theoverall coating is calculated from the difference between the respectivepoints of intersection of layer 3 with the environment or any furtherlayer applied with the environment and the respective baseline. Theheight h_(a) of the spacer layer is calculated from the differencebetween the respective measured points of intersection of spacer layerwith layer 3 and layer 2 with the spacer layer. The layer thicknesses ofany further layers applied can be determined analogously and should betaken into account correspondingly in forming the differences.

The individual values of the layer thicknesses and the height h_(a) thathave been determined in this way are used to form the respectivearithmetic means in order to determine the above-specified values forthe mean layer thicknesses and the mean height h_(a). To bestatistically meaningful, the above-described measurements are conductedon at least 100 of the parallel lines arranged at right angles to thebaselines.

The height h_(ma) refers to the midpoint of the spacer layer. It iscalculated as the sum total of the layer thickness of the optional layer1 and of layer 2 and half the height h_(a) of the spacer layer. Therelative height h_(Rma) of the midpoint of the spacer layer is formedfrom the ratio of h_(ma) and the layer thickness of the overall coating.The standard deviation of the relative height σh_(Rma) is preferablywithin a range from 0.2% to 18%, further preferably within a range from0.3% to 15%, more preferably within a range from 0.4% to 11% and mostpreferably within a range from 0.5% to 8%. The standard deviation of therelative height σh_(Rma) is a measure of the extent to which the spacerlayer is in a defined position parallel to the surface of thenonmetallic substrate in platelet form over the entire coating.

If the absorbent effect pigments of the invention have at least onefurther spacer layer, the height h_(ma) thereof and the relative heightof the midpoint of the at least one further spacer layer h_(Rma) thereofare ascertained via the above-described method using scanning electronmicrographs of transverse sections. The above-specified values forstandard deviation of the relative height σh_(Rma) apply correspondinglyto further spacer layers.

The person skilled in the art is aware that pearlescent pigments coatedwith titanium dioxide, for example, have pores in the coating that arestatistically distributed over the entire coating (FIG. 5). Thesepearlescent pigments do not have a spacer layer. The spacer layer andthe cavities present within the spacer layer in the absorbent effectpigments of the invention, by contrast, are not statisticallydistributed over the entire coating, but are arranged parallel to thesurface of the nonmetallic substrate in platelet form over the entirecoating.

The distances of the midpoints of the statistically distributed poresfrom the substrate surface were likewise determined by means of scanningelectron micrographs of transverse sections by the method describedabove. For this purpose, a sufficient number of parallel lines weredrawn at 50 nm intervals at a 90° angle with respect to the upper andlower baselines corresponding to the two surfaces of the substrate inplatelet form that a grid has been placed over the pearlescent pigmentwithout a spacer layer shown in the scanning electron micrograph of atransverse section. If one of the parallel lines occurred above one ormore pores, the height(s) thereof, the pore midpoint(s) thereof and thedistance of the pore midpoint(s) from the substrate surface weredetermined. The statistical distribution of the pore midpoints canlikewise be used to determine a standard deviation.

The standard deviation of the distances of the midpoints of thestatistically distributed pores from the substrate surface is >20% inpearlescent pigments from the prior art, i.e. in the case of pearlescentpigments without a spacer layer. The standard deviation of the distancesof the midpoints of the statistically distributed pores from thesubstrate surface is thus distinctly different in terms of its valuefrom the standard deviation of the relative height of the midpoint ofthe spacer layer of the absorbent effect pigments of the invention.

It is thus possible to compare the standard deviation of the distancesof the pore midpoints from the substrate surface of pearlescent pigmentswithout a spacer layer with the standard deviation of the relativeheight of the midpoint of the spacer layer of absorbent effect pigmentsof the invention.

In addition, with the aid of the above-described lines drawn at 50 nmintervals in a scanning electron micrograph, the number of connectionsor spacers per micrometer and the network density, defined as the numberof connections or spacers per number of lines in %, is determined.

If the absorbent effect pigments of the invention have more than onespacer layer within the overall coating, the method just described formeasuring the individual layers and the spacer layers is appliedcorrespondingly.

In one embodiment, the relative standard deviation in the heightdistribution of the spacer layer is 4% to 75%, preferably 7% to 69%,more preferably 9% to 63% and most preferably 13% to 60%. The relativestandard deviation in [%] of the height distribution is the quotient ofthe calculated standard deviation and the mean height.

In a preferred embodiment, the absorbent effect pigments of theinvention, within the at least one spacer layer, have a number ofconnections or spacers per micrometer from a range from 0 to 11, furtherpreferably from a range from 0 to 9, more preferably from a range from 1to 7 and most preferably from a range from 1 to 3.

In a preferred embodiment, the absorbent effect pigments of theinvention, within the at least one spacer layer, have a network density,defined as the number of connections or spacers per number of lines inpercent, of <85%, preferably from a range from 1% to 75%, morepreferably from a range from 1% to 63% and most preferably from a rangefrom 1% to 49%.

Above a network density of 85%, in the context of this invention,reference is no longer made to a spacer layer since the high proportionof connections or spacers then leads to a very substantially continuouscoating.

In a further preferred embodiment, the absorbent effect pigments of theinvention comprise at least one spacer layer arranged essentiallyparallel to the surface of the nonmetallic substrate in platelet form,where the at least one spacer layer in each case has a mean height h_(a)from a range from 19 nm to 83 nm, more preferably from a range from 27nm to 66 nm and most preferably from a range from 33 nm to 57 nm.

In a particularly preferred embodiment, the absorbent effect pigments ofthe invention have at least one spacer layer of mean height h_(a) from arange from 16 nm to 79 nm, preferably from a range from 21 nm to 66 nmand most preferably from a range from 23 nm to 57 nm, where the numberof connections or spacers per micrometer within the at least one spacerlayer is selected from a range from 0 to 8, preferably from a range from0 to 6, more preferably from a range from 1 to 5 and most preferablyfrom a range from 1 to 4.

The spacer layer comprises cavities as well as the above-describedconnections or spacers. These cavities are spatially bounded by layers 2and 3 and the connections or spacers.

Energy-dispersive x-ray microanalysis (EDX analysis) of these cavitiesdoes not permit any conclusion as to whether the material is solid orliquid, and so the inventors are assuming, with the methods of analysisavailable at present, that the cavities within the spacer layer comprisea gas, probably air. The connections or spacers, by contrast, compriseat least one metal oxide, metal hydroxide and/or metal oxide hydrate, asdetailed above.

The cavities within the spacer layer of the absorbent effect pigments ofthe invention may assume a mean height h_(H) from a range from 2 nm to119 nm, preferably from a range from 6 nm to 105 nm, more preferablyfrom a range from 11 nm to 85 nm and most preferably from a range from18 nm to 53 nm. The height h_(H) is understood to mean the greatestdifference between the uppermost and lowermost cavity boundaries. It isdetermined by the method described above for the height h_(a), bydrawing parallel lines at 50 nm intervals at a 90° angle to the surfaceof the nonmetallic substrate in platelet form in scanning electronmicrographs of transverse sections. The difference of the two points ofintersection of these lines with the upper and lower cavity boundariesis the height h_(H). Here too, to be statistically meaningful, theabove-described measurements are conducted on at least 100 lines.Therefore, the mean height h_(a) is a maximum value for the mean heighth_(H). Accordingly, it is also possible for a plurality of cavities tobe present one on top of another within the spacer layer.

The mean height of the spacer layer h_(a) and the mean height of thecavities h_(H) are determined, using a cured lacquer film in which theabsorbent effect pigments of the invention are aligned essentiallyplane-parallel to the substrate, according to the details given insection Ilk “Determination of the mean thickness of the nonmetallicsubstrates in platelet form, the mean layer thickness of layers 2 and 3,the mean layer thickness of the overall coating, the mean height h_(a)of the spacer layer and the mean height h_(H) of the cavities”. For thispurpose, a transverse section of the cured lacquer film is examinedunder a scanning electron microscope (SEM), as described above forh_(a). As an alternative to these transverse sections, the absorbenteffect pigments of the invention can be cut by means of the FIB method(FIB=focused ion beam). For this purpose, a fine beam of highlyaccelerated ions (for example gallium, xenon, neon or helium) is focusedto a point by means of ion optics and guided line by line over theeffect pigment surface to be processed. On impact with the effectpigment surface, the ions release most of their energy and destroy thecoating at this point, which leads to removal of material line by line.It is also possible using the scanning electron micrographs that havethen been recorded, by the method described above, to determine the meanheight h_(a), the mean layer thickness of layers 2 and 3 and the meanlayer thickness of the overall coating. The mean thickness of thenonmetallic substrate in platelet form can also be determined usingscanning electron micrographs of the effect pigments that have been cutby the FIB method.

In a further embodiment, the absorbent effect pigments of the inventioncomprise, within the spacer layer, distributed over the entire effectpigment and measured using scanning electron micrographs of transversesections, an area proportion of cavities from a range from 51% to 99%,preferably from a range from 63% to 96%, more preferably from a rangefrom 76% to 95% and most preferably from a range from 84% to 94%, and anarea proportion of connections or spacers from a range from 1% to 49%,preferably from a range from 4% to 37%, more preferably from a rangefrom 5% to 24% and most preferably from a range from 6% to 16%.

It is further preferable that the total volume occupied by theconnections and spacers in the spacer layer is less than the totalvolume occupied by the cavities.

Preferably, the total volume occupied by the connections or spacers inthe spacer layer is less than 50% by volume, further preferably lessthan 30% by volume, more preferably less than 20% by volume and mostpreferably less than 10% by volume of the total volume occupied by thecavities.

In the absorbent effect pigments of the invention, the cavities withinthe spacer layer, by contrast with the pores of the teaching accordingto EP 1 422 268 A2, are explicitly desired. According to EP 1 422 268A2, a coating with low porosity and a minimum number of pores isrequired to obtain pigments having high chroma and high brilliance. Thepigments according to EP 1 422 268 A2 do not have a spacer layer.According to the invention, the cavities that are not distributedrandomly within the overall coating but are present essentially parallelto the surface of the nonmetallic substrate in platelet form within thespacer layer do not have any adverse effect on the optical properties ofthe absorbent effect pigments of the invention. On the contrary, theabsorbent effect pigments of the invention, compared to pigments with asingle-layer coating, feature higher gloss and higher chroma, naturallyassuming the same nonmetallic substrate in platelet form, the sameparticle size and an identical first coating. At the same time,depending on the coating thickness and the type of coating, differentinterference colors and/or different absorption colors can be obtained.

The higher gloss and the higher chroma can be explained by the maximumdifference in refractive index between the spacer layer and theadjoining layers, which, according to Fresnel's law, leads in each caseto a maximum reflection of light at these interfaces. For the cavities,the basis used here is the refractive index of air of approximately 1. Alight beam hitting the spacer layer is partly reflected at theinterfaces thereof, the respective intensity of the reflection accordingto Fresnel's law being dependent on the difference in refractive indexof the adjoining layers from the spacer layer. Since such partialreflection takes place at every single interface, the total reflectionalso increases with the number of interfaces. In absorbent effectpigments of the invention, a light beam is thus partly reflected onmultiple occasions, the effect of which is much more intense gloss andmuch greater intensity of the interference color compared toconventional, singly coated pigments.

If the cavities are statistically distributed within the overallcoating, i.e. not essentially parallel to the nonmetallic substrate inplatelet form, there will be a variation in the optical path lengthwithin the overall coating. The result of this is that the interferenceconditions are not adequately fulfilled and hence there will be noamplification or extinction.

The gloss of the absorbent effect pigments of the invention isdetermined using white/black hiding cards with the aid of aMicro-Tri-Gloss gloss meter from Byk-Gardner, according to the detailsgiven hereinafter in section IId “Gloss measurements”. The chroma of theabsorbent effect pigments of the invention is likewise determined usingwhite/black hiding cards with the BYK-mac multi-angle colorimeter (fromByk-Gardner), according to the details given hereinafter in section IIb“Angle-dependent color measurements”. Further optical effects, such assparkles and graininess, are determined according to the details givenhereinafter in section Ile “Effect measurements”.

In one embodiment, the absorbent effect pigments of the inventioncomprise, as well as the above-described layers 1, 2 and 3, furtherlayers of high and/or low refractive index, which may be arranged,viewed from the nonmetallic substrate in platelet form, either below theoptional layer 1 or layer 2 and/or above layer 3. These further layersmay comprise metal oxides, metal hydroxides, metal oxide hydrates, wherethe metal ions of the metal oxides, metal hydroxides, metal oxidehydrates comprise or are at least one metal ion selected from the groupof metals consisting of Ti, Fe, Sn, Mn, Zr, Ca, Sr, Ba, Ni, Ag, Zn, Cu,Ce, Cr and Co, preferably selected from the group of metals consistingof Ti, Fe, Sn, Zr, Ag, Zn, Cu, Ce, Cr and more preferably selected fromthe group of metals consisting of Ti, Fe and Sn. Moreover, these furtherlayers may comprise semitransparent metals selected from the groupconsisting of Ag, Al, Cr, Ni, Au, Pt, Pd, Cu, Zn and Ti, preferablyselected from the group consisting of Ag, Au and Cu, the alloys of eachand/or mixtures thereof. According to the invention, the further layersare selected such that the proportion of coloring metal ions selectedfrom the group of metals consisting of Fe, Ti, Sn, Mn, Cu, Cr, Co, Agand Ce, determined in each case by means of XRF and calculated in eachcase as the elemental metal, preferably totals >4% by weight, and isfurther preferably within a range from 5% by weight to 82% by weight intotal, more preferably within a range from 7% by weight to 72% by weightin total and most preferably within a range from 10% by weight to 68% byweight in total, based in each case on the total weight of the absorbenteffect pigment. Moreover, the proportion of at least one semitransparentmetal, determined by means of XRF, preferably totals ≥1% by weight, andis more preferably within a range from 2% by weight to 20% by weight intotal and most preferably within a range from 3% to 12% by weight intotal, based in each case on the total weight of the absorbent effectpigment. If the absorbent effect pigments of the invention comprise atleast one coloring metal ion and at least one semitransparent metal,regardless of whether they are in the nonmetallic substrate in plateletform or in the coating, the proportion thereof preferably totals ≥5% byweight, based on the total weight of the absorbent effect pigment.

In one embodiment, each of the layers of the absorbent effect pigmentsof the invention may be provided with a dopant, where the dopant maycomprise metal oxides, metal hydroxides and/or metal oxide hydrates, andthe metal ions of the metal oxides, metal hydroxides and/or metal oxidehydrates comprise or are at least one metal ion selected from the groupof metals consisting of Ca, Mg, Al, Ce, Zr or Sn, preferably Al, Zr orSn. The proportion of dopant preferably totals ≤1% by weight, morepreferably totals ≤0.5% by weight and most preferably totals ≤0.2% byweight, based in each case on the total weight of the absorbent effectpigments.

In a further embodiment, the overall coating of the absorbent effectpigments of the invention may, as well as the spacer layer, comprise atleast one further spacer layer also arranged essentially parallel to thesurface of the nonmetallic substrate in platelet form between layers 2and 3. Preferably, the absorbent effect pigments of the invention havenot more than four spacer layers within the overall coating, since theoptical quality thereof then decreases. According to the invention, evenwhen the absorbent effect pigment of the invention comprises more thanone spacer layer, in relation to the overall coating, there is no spacerlayer either in the first sixth or in the sixth sixth of the overallcoating.

The absorbent effect pigments of the invention may have any medianparticle size D₅₀. The D₅₀ values of the absorbent effect pigments ofthe invention are preferably within a range from 3 μm to 350 μm.Preferably, the D₅₀ values of the absorbent effect pigments of theinvention are within a range from 4 μm to 211 μm, further preferablywithin a range from 6 μm to 147 μm, more preferably within a range from7 μm to 99 μm and most preferably within a range from 8 μm to 56 μm.Exceptionally preferably, the absorbent effect pigments of the inventionhave a D₅₀ from a range from 3 μm to 15 μm or from a range from 10 μm to35 μm or from a range from 25 μm to 45 μm or from a range from 30 μm to65 μm or from a range from 40 μm to 140 μm or from a range from 135 μmto 250 μm.

The D₁₀ values of the absorbent effect pigments of the inventionpreferably encompass a range from 1 μm to 120 μm. More preferably, theD₁₀ values of the absorbent effect pigments of the invention are withina range from 1 μm to 5 μm or within a range from 5 μm to 25 μm or withina range from 10 μm to 30 μm or within a range from 20 μm to 45 μm orwithin a range from 25 μm to 65 μm or within a range from 75 μm to 110μm.

The D₉₀ values of the absorbent effect pigments of the inventionpreferably encompass a range from 6 μm to 500 μm. More preferably, theD₉₀ values of the absorbent effect pigments of the invention are withina range from 8 μm to 250 μm or within a range from 10 μm to 150 μm orwithin a range from 40 μm to 70 μm or within a range from 68 μm to 110μm or within a range from 120 μm to 180 μm or within a range from 400 μmto 490 μm.

The D₁₀, D₅₀ and D₉₀ of the cumulative frequency distribution of thevolume-averaged size distribution function, as obtained by laserdiffraction methods, indicates that, respectively, 10%, 50% and 90% ofthe effect pigments analyzed have a volume-averaged diameter less thanor equal to the value specified in each case. In this context, the sizedistribution curve of the absorbent effect pigments of the invention isdetermined using the Malvern Mastersizer 2000 instrument according tothe manufacturer's instructions. The scattered light signals areevaluated by the Fraunhofer theory, which also includes diffraction andabsorption characteristics of the particles.

In a preferred embodiment, the absorbent effect pigments of theinvention have a span ΔD, defined as ΔD=D₉₀-D₁₀/D₅₀, from a range from0.7 to 2.0, preferably from a range from 0.7 to 1.5, further preferablyfrom a range from 0.8 to 1.3, more preferably from a range from 0.8 to1.2 and most preferably from a range from 0.85 to 1.1. The advantages ofa narrow size classification in relation to color purity and/or gloss ofthe resulting effect pigments are described, for example, in EP 2 217664 A1, EP 2 346 950 A1, EP 2 356 181 A1, EP 2 346 949 A1, EP 2 367 889A1.

The absorbent effect pigments of the invention can be produced asfollows:

-   -   suspending the nonmetallic substrates in platelet form in water        at a temperature from a range from 50° C. to 100° C.,    -   optionally applying an uncalcined layer comprising or consisting        of tin oxide, tin hydroxide and/or tin oxide hydrate by adding a        water-soluble tin salt with simultaneous addition of a mineral        alkali,    -   sequentially applying three uncalcined layers A, B and C in the        form of metal oxides, metal hydroxides and/or metal oxide        hydrates by sequential addition of three water-soluble metal        salts, in each case with simultaneous addition of mineral        alkali, where the second water-soluble metal salt—for production        of layer B—is different in relation to the metal ion than the        two other water-soluble metal salts for production of layer A        and layer C,    -   separating the coated substrates from the coating solution(s),        and optionally washing and/or optionally drying the coated        substrates,    -   calcining the coated substrates at temperatures from a range        from 600° C. to 1100° C., preferably from a range from 625° C.        to 930° C. and more preferably from a range from 750° C. to        890° C. to obtain the absorbent effect pigments of the invention        comprising at least one spacer layer.

In a preferred embodiment, the absorbent effect pigments of theinvention are produced by the above process.

The application, preferably deposition, of the respective metal oxides,metal hydroxides and/or metal oxide hydrates is preferably effected at aconstant pH within a range from pH 1.4 to 10.0 depending on the metalsalt.

In addition to the at least three sequentially applied, preferablydeposited, metal oxides, metal hydroxides and/or metal oxide hydrates,it is of course also possible for further metal oxides, metal hydroxidesand/or metal oxide hydrates to be applied beforehand and/orsubsequently, such that further layers may be arranged beneath or abovethe layer sequence [optional layer 1/layer 2/spacer layer/layer 3].

In the course of calcining, there is surprisingly diffusion presumablyof the metal ions present in the layer B into layer A and/or layer C toform mixed metal oxides and/or mixed metal hydroxides and/or metal oxidehydrates and/or mixtures of metal oxides and/or metal hydroxides and/ormetal oxide hydrates in layer A and/or layer C. Because of the diffusionof the metal ions from layer B into layer A and/or layer C in the courseof calcining, layers 2 and 3 of the invention and the intermediatespacer layer are formed, with at least one of the two layers 2 and 3comprising at least two different metal ions. The originally threesuccessively deposited layers A, B and C thus give rise, in the courseof calcining, to layers 2 and 3 and the intermediate spacer layer, withat least one of the two layers 2 and 3 comprising at least two differentmetal ions.

It is assumed that the different mobility of the metal oxides, metalhydroxides and/or metal oxide hydrates with respect to one another inthe course of calcining is one of the factors responsible for theformation of the spacer layer. In this context, the mobility of themetal ions present in layer B competes with the mobility of the metalions present in layers A and/or C, assuming that the metal ions diffuseout of layer B into at least one of the adjoining layers A and/or C andthe metal ions diffuse from at least one of layers A and/or C into layerB. The inventors are assuming at present that, if the mobility of themetal ions present in layer B during the calcination is higher than themobility of the metal ions present in layers A and/or C, is one of thepossible explanations for the formation of the spacer layer.Furthermore, it is assumed that a concentration gradient in relation tothe metal ions promotes the formation of a spacer layer, i.e. when moremobile metal ions can diffuse out of layer B into one of the adjoininglayers A and/or C than in the reverse direction. In summary, it has beenfound that the formation of a spacer layer is caused by a complexinterplay of a wide variety of different further factors, for exampleentropic and/or enthalpic effects, during the calcination, but thesehave not yet been conclusively clarified. For the formation of at leastone further spacer layer, the above considerations naturally applycorrespondingly.

In a preferred embodiment, the first and third of the three sequentiallyapplied, preferably deposited, metal oxides, metal hydroxides and/ormetal oxide hydrates comprise at least one metal ion selected from thegroup of metals consisting of Fe, Ti and Sn. The first and third metaloxides, metal hydroxides and/or metal oxide hydrates, after application,respectively produce layer A and layer C. The second of the threesequentially applied, preferably deposited, metal oxides, metalhydroxides and/or metal oxide hydrates produces layer B and comprises atleast one metal ion selected from the group of metals consisting of Fe,Sn, Zr and Ce, which is different than the metal ions of the metaloxides, metal hydroxides and/or metal oxide hydrates deposited forproduction of layer A and layer C. In layer A and layer C, the metaloxides, metal hydroxides and/or metal oxide hydrates applied, preferablydeposited, may be the same or different in relation to the metal ion(s).

Alternatively, the absorbent effect pigments of the invention can beproduced as follows:

-   -   suspending the calcined, singly or multiply coated nonmetallic        substrates in platelet form in water at a temperature from a        range from 50° C. to 100° C.,    -   sequentially applying two uncalcined layers B and C in the form        of metal oxides, metal hydroxides and/or metal oxide hydrates by        sequential addition of two water-soluble metal salts, in each        case with simultaneous addition of mineral alkali, where the        first water-soluble metal salt—for production of layer B—is        different in relation to the metal ion than the other        water-soluble metal salt for production of layer C and the layer        that directly adjoins layer B in the substrate direction,    -   separating the coated substrates from the coating solution(s),        and optionally washing and/or optionally drying the coated        substrates,    -   calcining the coated substrates at temperatures from a range        from 600° C. to 1100° C., preferably from a range from 625° C.        to 930° C. and more preferably from a range from 750° C. to        890° C. to obtain the absorbent effect pigments of the invention        comprising at least one spacer layer.

Here too, the application, preferably deposition, of the respectivemetal oxides, metal hydroxides and/or metal oxide hydrates is preferablyeffected at a constant pH within a range from pH 1.4 to 10.0 dependingon the metal salt.

It is suspected that, in the course of calcining, the metal ions presentin the layer B diffuse at least into layer C to form mixed metal oxidesand/or mixed metal hydroxides and/or metal oxide hydrates and/ormixtures of metal oxides and/or metal hydroxides and/or metal oxidehydrates in layer C. Because of the diffusion of the metal ions fromlayer B into layer C, the calcining forms layer 3 of the invention andthe spacer layer. The originally two successively deposited layers B andC thus give rise, in the course of calcining, to layer 3 and the spacerlayer, with at least layer 3 comprising at least two different metalions. Layer 2 is already present here. Layer 2 refers to the outermostlayer of the calcined, singly or multiply coated nonmetallic substratein platelet form which is used as starting material.

The concentration profile (line scan) on the basis of transversesections in the scanning electron microscope with an energy-dispersivemicroanalyzer (EDX) shows a significant location-dependent change in thechemical composition of the coating before and after calcination (FIGS.8 and 9).

FIG. 8 shows a concentration profile of example 12 after coating anddrying, but before calcination. Using the concentration curves of Ti andFe, it is possible to recognize the maxima in each case of the Ti- andFe-containing layers. The concentration curve of oxygen, by contrast,has a substantially homogeneous distribution without recognizable minimaor maxima.

FIG. 9 likewise shows a concentration profile of example 12 aftercoating and drying, but after calcination. It is found that the Femaximum present in FIG. 9 has been reduced and shifted. The Fe ions havediffused into the surrounding Ti-containing layers. What shouldadditionally be emphasized is a marked minimum in the oxygenconcentration curve which clearly indicates the position of the spacerlayer. At the same position, there are corresponding minima in theconcentration curves of Ti and Fe.

In a particularly preferred embodiment, the two or three sequentiallyapplied, preferably deposited, metal oxides, metal hydroxides and/ormetal oxide hydrates for production of the layers B and C or A, B and Cdo not comprise any metal ion(s) selected from the group of the metalsconsisting of Si, Mg and Al.

In the case of sequential application of two uncalcined layers B and Cto an already coated and optionally calcined substrate, that layer towhich the layer B is applied, in accordance with the invention,comprises a metal oxide, metal hydroxide and/or metal oxide hydrate ofhigh refractive index.

In the case of sequential application of three uncalcined layers A, Band C to an already coated and optionally calcined substrate, that layerto which the layer A is applied, in accordance with the invention, maycomprises a metal oxide, metal hydroxide and/or metal oxide hydrate ofhigh or low refractive index.

The above remarks are elucidated in detail hereinafter by way of examplewith reference to various coatings.

If, for example, a water-soluble titanium(IV) salt, a water-solubleiron(III) salt and a water-soluble titanium(IV) salt again are appliedsuccessively to a suspension of an optionally coated nonmetallicsubstrate in platelet form, the calcination, viewed proceeding from thesubstrate in the SEM transverse section, following the coating which isoptionally already present, gives rise to a layer 2 comprising a metaloxide, metal hydroxide and/or metal oxide hydrate, where the metal ionsof the metal oxide, metal hydroxide and/or metal oxide hydrate compriseor are titanium ions and/or iron ions, a spacer layer, and a layer 3comprising a metal oxide, metal hydroxide and/or metal oxide hydrate,where the metal ions of the metal oxide, metal hydroxide and/or metaloxide hydrate comprise or are titanium ions and/or iron ions. At leastone of the layers comprising a metal oxide, metal hydroxide and/or metaloxide hydrate, where the metal ions of the metal oxide, metal hydroxideand/or metal oxide hydrate comprise or are titanium ions and/or ironions, comprises an iron titanate, preferably pseudobrookite and/orpseudorutile. In relation to the amounts used, the above remarksrelating to coloring and noncoloring metal ions are applicable here too.

If, for example, a water-soluble titanium(IV) salt is added to asuspension of the optionally coated nonmetallic substrate in plateletform and calcined following deposition of titanium dioxide, titaniumhydroxide and/or titanium oxide hydrate, this product is resuspendedafter the calcination and a water-soluble iron(III) salt and awater-soluble tin(IV) salt are added successively, another calcination,viewed proceeding from the substrate in the SEM transverse section,following the coating which is optionally already present and layer 2comprising a metal oxide, metal hydroxide and/or metal oxide hydrate,where the metal ion of the metal oxide, metal hydroxide and/or metaloxide hydrate comprises or is titanium ions, gives rise to a spacerlayer and a layer 3 comprising a metal oxide, metal hydroxide and/ormetal oxide hydrate, where the metal ion of the metal oxide, metalhydroxide and/or metal oxide hydrate comprises or is iron ions and/ortin ions.

If the absorbent effect pigments of the invention, in addition to the atleast two or three sequentially applied, preferably deposited, metaloxides, metal hydroxides and/or metal oxide hydrates, include furtherlayers comprising metal oxides, metal hydroxides and/or metal oxidehydrates, it is also possible for further spacer layers to form withinthe further layers, provided that the process steps described above forthe at least two or three sequentially applied, preferably deposited,metal oxides, metal hydroxides and/or metal oxide hydrates are observed.

In one embodiment, the calcination is effected under reducingconditions, preferably in the presence of forming gas (N₂/H₂). Acalcination under reducing conditions can be associated with lowerbrightness values L* than is the case for calcination under air.

The absorbent effect pigments of the invention may optionally beprovided with at least one outer protective layer that further increasesweathering stability and/or chemical stability and/or further reducesphotoactivity. The UV stability and the condensate water stability weredetermined according to the details given below in the sections IIj “UVstability” and IIi “Condensate water test”.

The optionally present protective layer comprises metal oxides, metalhydroxides and/or metal oxide hydrates wherein the metal ions areselected from the group of metals consisting of Si, Ce, Cr, Al, Zr, Znand mixtures thereof, preferably from the group of metals Si, Ce, Al, Zrand mixtures thereof. In this context, the proportion of the optionallypresent protective layer is preferably within a range from 0.1% byweight to 7.0% by weight, more preferably within a range from 0.2% byweight to 5.2% by weight and most preferably within a range from 0.3% byweight to 3.1% by weight, based in each case on the total weight of theabsorbent effect pigment of the invention.

The optionally present protective layer may additionally have beensurface modified, for example by silanes. The silanes may have nofunctional bonding group or one or more functional bonding group(s).Silanes having at least one functional bonding group are also referredto hereinafter as organofunctional silanes.

For example, one or more silanes may have been applied to this outermostprotective layer. The silanes may be alkylsilanes having branched orunbranched alkyl radicals having 1 to 24 carbon atoms, preferably 6 to18 carbon atoms.

In a further preferred embodiment, the silane without a functionalbonding group is an alkylsilane. The alkylsilane preferably has theformula R_((4-z))Si(X)_(z). In this formula, z is an integer from 1 to3, R is a substituted or unsubstituted, unbranched or branched alkylchain having 10 to 22 carbon atoms, and X is a halogen and/or alkoxygroup. Preference is given to alkylsilanes having alkyl chains having atleast 12 carbon atoms. R may also be bonded to Si in a cyclic manner, inwhich case z is typically 2.

In a further embodiment, it is also possible to use at least oneorganofunctional silane which enables a chemical bond to a plastic, or abinder of a lacquer or a paint, etc., for surface modification. Thesegroups of the organofunctional silane may also be referred to ascoupling groups or functional bonding groups and are preferably selectedfrom the group consisting of hydroxyl, amino, acryloyl, methacryloyl,vinyl, epoxy, isocyanate, cyano and mixtures thereof.

The organofunctional silanes having suitable functional groups that areused with preference as surface modifiers are commercially available andare produced, for example, by Evonik and sold under the “Dynasylan”trade name. Further products can be purchased from Momentive (Silquestsilanes) or from Wacker, for example standard silanes and α-silanes fromthe GENIOSIL product group. Examples of these are3-methacryloyloxypropyltrimethoxysilane (Dynasylan MEMO, SilquestA-174NT), vinyltri(m)ethoxysilane (Dynasylan VTMO and VTEO, SilquestA-151 and A-171), methyltri(m)ethoxysilane (Dynasylan MTMS and MTES),3-mercaptopropyltrimethoxysilane (Dynasylan MTMO; Silquest A-189),3-glycidoxypropyltrimethoxysilane (Dynasylan GLYMO, Silquest A-187),tris[3-(trimethoxysilyl)propyl]isocyanurate (Silquest Y-11597),bis[3-(triethoxysilyl)propyl)]tetrasulfide (Silquest A-1289),bis[3-(triethoxysilyl)propyl disulfide (Silquest A-1589),beta-(3,4-epoxycyclohexyl)ethyltrimethoxysi lane (Silquest A-186),bis(triethoxysilyl)ethane (Silquest Y-9805),gamma-isocyanatopropyltrimethoxysilane (Silquest A-Link 35, GENIOSILGF40), methacryloyloxymethyltri(m)ethoxysilane (GENIOSIL XL 33, XL 36),(methacryloyloxymethyl)(m)ethyldimethoxysilane (GENIOSIL XL 32, XL 34),(isocyanatomethyl)methyldimethoxysilane,(isocyanatomethyl)trimethoxysilane, 3-(triethoxysilyl)propylsuccinicanhydride (GENIOSIL GF 20), (methacryloyloxymethyl)methyldiethoxysilane,2-acryloyloxyethylmethyldimethoxysilane,2-methacryloyloxyethyltrimethoxysilane,3-acryloyloxypropylmethyldimethoxysilane,2-acryloyloxyethyltrimethoxysilane,2-methacryloyloxyethyltriethoxysilane,3-acryloyloxypropyltrimethoxysilane,3-acryloyloxypropyltripropoxysilane,3-methacryloyloxypropyltriethoxysilane,3-methacryloyloxypropyltriacetoxysilane,3-methacryloyloxypropylmethyldimethoxysilane, vinyltrichlorosilane,vinyltrimethoxysilane (GENIOSIL XL 10), vinyltris(2-methoxyethoxy)silane(GENIOSIL GF 58), vinyltriacetoxysilane or mixtures thereof. Preferenceis given to using, as organofunctional silanes,3-methacryloyloxypropyltrimethoxysilane (Dynasylan MEMO, SilquestA-174NT), vinyltri(m)ethoxysilane (Dynasylan VTMO and VTEO, SilquestA-151 and A-171), methyltri(m)ethoxysilane (Dynasylan MTMS and MTES),beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (Silquest A-186),bis(triethoxysilyl)ethane (Silquest Y-9805),gamma-isocyanatopropyltrimethoxysilane (Silquest A-Link 35, GENIOSILGF40), methacryloyloxymethyltri(m)ethoxysilane (GENIOSIL XL 33, XL 36),(methacryloyloxymethyl)(m)ethyldimethoxysilane (GENIOSIL XL 32, XL 34),3-(triethoxysilyl)propylsuccinic anhydride (GENIOSIL GF 20),vinyltrimethoxysilane (GENIOSIL XL 10) and/orvinyltris(2-methoxyethoxy)silane (GENIOSIL GF 58).

It is also possible to apply other organofunctional silanes to theparticles of the invention or the pigments of the invention.

In addition, it is possible to use aqueous prehydrolyzates commerciallyavailable, for example, from Degussa. These include aqueousaminosiloxane (Dynasylan Hydrosil 1151), aqueous amino-/alkyl-functionalsiloxane (Dynasylan Hydrosil 2627 or 2909), aqueous diamino-functionalsiloxane (Dynasylan Hydrosil 2776), aqueous epoxy-functional siloxane(Dynasylan Hydrosil 2926), amino-/alkyl-functional oligosiloxane(Dynasylan 1146), vinyl-/alkyl-functional oligosiloxane (Dynasylan6598), oligomeric vinylsilane (Dynasylan 6490) or oligomeric short-chainalkyl-functional silane (Dynasylan 9896).

In a preferred embodiment, the organofunctional silane mixture, as wellas at least one silane without a functional bonding group, comprises atleast one amino-functional silane. The amino function is a functionalgroup which can enter into one or more chemical interactions with mostof the groups present in binders. This may include a covalent bond, forexample with isocyanate or carboxylate functions of the binder, orhydrogen bonds such as with OH or COOR functions, or else ionicinteractions. An amino function is therefore of very good suitabilityfor the purpose of chemical attachment of the pigment to various kindsof binder.

Preference is given to taking the following compounds for this purpose:3-aminopropyltrimethoxysilane (Dynasylan AMMO; Silquest A-1110),3-aminopropyltriethoxysilane (Dynasylan AMEO),[3-(2-aminoethyl)aminopropyl]trimethoxysilane (Dynasylan DAMO, SilquestA-1120), [3-(2-aminoethyl)aminopropyl]triethoxysilane,triamino-functional trimethoxysilane (Silquest A-1130),bis(gamma-trimethoxysilylpropyl)amine (Silquest A-1170),N-ethyl-gamma-aminoisobutyltrimethoxysilane (Silquest A-Link 15),N-phenyl-gamma-aminopropyltrimethoxysilane (Silquest Y-9669),4-amino-3,3-dimethylbutyltrimethoxysilane (Silquest A-1637),((cyclohexylamino)methyl)(diethoxy)methylsilane (GENIOSIL XL 924),N-cyclohexylaminomethyltriethoxysilane (GENIOSIL XL 926),N-(phenylaminomethyl)trimethoxysilane (GENIOSIL XL 973) or mixturesthereof.

In a preferred embodiment, the optionally present protective layer hasthe composition disclosed in the respective main claims of WO2006/021386 A1, WO 2012/130897 A1 or WO 2014/053454 A1.

In addition, the absorbent effect pigments of the invention may havebeen provided with a surface modification which, for example,facilitates the incorporation of the effect pigments into differentmedia. In the case of use of the absorbent effect pigments of theinvention in powder coatings, for example, the effect pigmentspreferably have one of the surface modifications disclosed in the mainclaims of EP 2 698 403 A1 or of EP 2 576 702 A1. Alternatively, theabsorbent effect pigments of the invention may also have an outermostcoating according to WO 2006/136435 A2, claim 32, which is preferablyapplied by the spray drying method according to WO 2006/136435 A2, claim1.

In the case of use of the absorbent effect pigments of the invention incosmetic formulations, the incorporation thereof into 0/W, W/0 or W/Siemulsion systems, for example, can be facilitated by hydrophobic surfacecoverage, for example with triethoxycaprylylsilane, and more prolongedemulsion stability can be achieved.

The absorbent effect pigments of the invention can also be used inmixtures with transparent and/or hiding (in)organic white, chromatic orblack pigments and/or metal effect pigments and/or pearlescent pigmentsand/or fillers in the application desired in each case. The amount inwhich the absorbent effect pigments of the invention are used depends onthe particular application and on the optical effect to be achieved.

The absorbent effect pigments of the invention can be used in cosmeticformulations, plastics, films, textiles, ceramic materials, glasses,paints, printing inks, writing inks, lacquers and powder coatings. Inaddition, the absorbent effect pigments of the invention can also beused for functional applications, for example laser marking, greenhousefilms or agricultural films.

In cosmetic formulations, for example body powder, face powder, pressedor loose powder, powder cream, eye makeup such as eyeshadow, mascara,eyeliner, liquid eyeliner, eyebrow pencil, lip balm, lipstick, lipgloss, lip liner, hair styling compositions such as hair spray, hairmousse, hair gel, hair wax, hair mascara, permanent or semipermanenthair dyes, temporary hair dyes, skincare compositions such as lotions,gels, emulsions, nail varnish compositions, it is possible to combinethe absorbent effect pigments of the invention with raw materials,auxiliaries and active ingredients suitable for the particularapplication. The total concentration of absorbent effect pigments of theinvention in the cosmetic formulation may be between 0.001% by weightfor rinse-off products and 40.0% by weight for leave-on products, basedin each case on the total weight of the formulation.

In a further embodiment, the absorbent effect pigments of the inventionmay be in compact particulate form. Compact particulate form isunderstood to mean pellets in the form of preferably cylinders and/orbeads. The cylinders here preferably have a diameter from a range from0.2 cm to 4.2 cm, more preferably from a range from 0.5 cm to 2.3 cm andmost preferably from a range from 0.7 cm to 1.7 cm, and preferably alength from a range from 0.2 cm to 7.1 cm, more preferably from a rangefrom 0.6 cm to 5.3 cm and most preferably from a range from 0.8 cm to3.7 cm. The beads preferably have a radius of 1 cm, more preferably froma range from 0.2 cm to 0.7 cm and most preferably from a range from 0.3cm to 0.5 cm.

In a further embodiment, the present invention relates to an absorbenteffect pigment comprising a nonmetallic substrate in platelet form,preferably a synthetic mica platelet or a glass platelet, and a coatingapplied thereto, wherein the coating comprises

-   a) optionally a layer 1 comprising or consisting of tin oxide, tin    hydroxide and/or tin oxide hydrate,-   b) a layer 2 comprising at least one metal oxide, metal hydroxide    and/or metal oxide hydrate, where the metal ion comprises or is at    least one metal ion selected from the group of metals consisting of    Ti, Sn and Fe,-   c) a layer 3 comprising at least one metal oxide, metal hydroxide    and/or metal oxide hydrate, where the metal ion comprises or is at    least one metal ion selected from the group of metals consisting of    Ti, Sn, Ce and Fe,    where at least one of layers 2 and 3 comprises at least two    different metal ions from the groups listed above, where the    proportion of coloring metal ions, determined in each case via XRF    and calculated in each case as the elemental metal, is within a    range from 7.5% by weight to 75% by weight, based on the total    weight of the effect pigment, layers 2 and 3 are interrupted by a    spacer layer of mean height h_(a) from a range from 10 nm to 66 nm,    the standard deviation of the relative height h_(Rma) is within a    range from 0.2% to 11%, and the network density is within a range    from 1% to 79%.

In a further embodiment, the present invention relates to an absorbenteffect pigment comprising a nonmetallic substrate in platelet form,preferably a synthetic mica platelet or a glass platelet, and a coatingapplied thereto, wherein the coating comprises

-   a) optionally a layer 1 comprising or consisting of tin oxide, tin    hydroxide and/or tin oxide hydrate,-   b) a layer 2 comprising at least one metal oxide, metal hydroxide    and/or metal oxide hydrate, where the metal ion comprises or is at    least one noncoloring metal ion selected from the group of metals    consisting of Fe, Ti, Sn and Zr,-   c) a layer 3 comprising at least one metal oxide, metal hydroxide    and/or metal oxide hydrate, where the metal ion comprises or is at    least one noncoloring metal ion selected from the group of metals    consisting of Fe, Ti, Sn and Zr,    and at least one of layers 2 and 3 comprises at least two different    metal ions from the groups listed above, layers 2 and 3 are    interrupted by a spacer layer, and where the effect pigments have a    span ΔD from a range from 0.8 to 1.9.

In a preferred embodiment, the present invention relates to an absorbenteffect pigment comprising a nonmetallic substrate in platelet form,preferably a synthetic mica platelet or a glass platelet, and a coatingapplied thereto, wherein the coating comprises

-   a) optionally a layer 1 comprising or consisting of tin oxide, tin    hydroxide and/or tin oxide hydrate,-   a) a layer 2 comprising at least one metal oxide, metal hydroxide    and/or metal oxide hydrate composed of or comprising at least one    metal ion selected from the group of metals consisting of Ti, Fe, Sn    and Zr,-   b) a layer 3 comprising at least one metal oxide, metal hydroxide    and/or metal oxide hydrate composed of or comprising at least one    metal ion selected from the group of metals consisting of Ti, Fe, Sn    and Zr,    and at least one of layers 2 and 3 comprises at least two different    metal ions from the groups listed above, where the proportion of    coloring metal ions, determined in each case via XRF and calculated    in each case as the elemental metal, is within a range from 4.0% by    weight to 79% by weight in total, preferably within a range from    5.0% by weight to 72% by weight, based in each case on the total    weight of the effect pigment, layers 2 and 3 are interrupted by a    spacer layer and the effect pigment has a chemical resistance with a    dE of <3, preferably <2.

In a particularly preferred embodiment, the present invention relates toan absorbent effect pigment comprising a nonmetallic substrate inplatelet form, preferably a synthetic mica platelet or a glass platelet,and a coating applied thereto, wherein the coating comprises

-   a) optionally a layer 1 comprising or consisting of tin oxide, tin    hydroxide and/or tin oxide hydrate,-   b) a layer 2 comprising at least one metal oxide, metal hydroxide    and/or metal oxide hydrate, where the metal ions comprise or are at    least two metal ions selected from the group of metals consisting of    Fe and Sn,-   c) a layer 3 comprising at least one metal oxide, metal hydroxide    and/or metal oxide hydrate, where the metal ions comprise or are at    least two metal ions selected from the group of metals consisting of    Fe and Sn,    and layers 2 and 3 are interrupted by a spacer layer, where the    coating comprises further layers of high and/or low refractive index    and the effect pigment comprises at least one further spacer layer    which runs essentially parallel to the surface of the nonmetallic    substrate in platelet form and is of mean height h_(a) from a range    from 11 nm to 76 nm, preferably from a range from 19 nm to 54 nm.

In a further embodiment, the present invention relates to an absorbenteffect pigment comprising a nonmetallic substrate in platelet form,preferably a synthetic mica platelet or a glass platelet, and a coatingapplied thereto, wherein the coating comprises

-   a) optionally a layer 1 comprising or consisting of tin oxide, tin    hydroxide and/or tin oxide hydrate,-   b) a layer 2 comprising at least one metal oxide, metal hydroxide    and/or metal oxide hydrate, where the metal ion comprises or is at    least one metal ion selected from the group of metals consisting of    Zr, Sn and Fe,-   c) a layer 3 comprising at least one metal oxide, metal hydroxide    and/or metal oxide hydrate, where the metal ion comprises or is at    least one metal ion selected from the group of metals consisting of    Zr, Sn, Ce and Fe,    where at least one of the layers 2 and 3 comprises at least two    different metal ions from the groups listed above, the quotient of    the mean layer thickness of layer 2 and the mean layer thickness of    layer 3 is preferably within a range from 0.5 to 1.8, and the    standard deviation of the relative height h_(Rma) is within a range    from 0.2% to 11%.

In a further embodiment, the absorbent effect pigments of the inventionhave a hue angle h*₁₅ within the CIE LCh color space from a range from0° to 60° and 120° to 360°, further preferably from a range from 0° to45° and 135° to 360°, more preferably from a range from 0° to 35° and140° to 360°, and most preferably from a range from 0° to 30° and 145°to 360°. Preferably, the chroma C*15 within the aforementioned hue angleranges is >15, more preferably >20 and most preferably >30. The hueangle h*₁₅ and the chroma C*₁₅ are determined here using lacquerapplications, on black/white hiding charts (Byko-Chart 2853, fromByk-Gardner), of a nitrocellulose lacquer (Erco 2615e bronze mixinglacquer colorless; from Maeder Plastiklack AG) which has been admixedwith 6% by weight of the particular effect pigment of the invention,according to the details which follow in section IIb “Angle-dependentcolor measurements”.

The CIE LCh color space is the CIELab color space, wherein the cylindercoordinates C* (chroma, relative color saturation, distance from the Laxis) and h* (hue angle, angle of the hue in the CIELab color circle)are reported rather than the Cartesian coordinates a*, b*.

In a further embodiment, the present invention relates to an absorbenteffect pigment comprising a nonmetallic substrate in platelet form,preferably a synthetic mica platelet or a glass platelet, and a coatingapplied thereto, where the coating has through at least one spacer layeressentially parallel to the surface of the nonmetallic substrate inplatelet form and the effect pigment is obtainable by i) optionallyapplying an uncalcined tin oxide, tin hydroxide and/or tin oxide hydratelayer to the nonmetallic substrate in platelet form, ii) applying threeuncalcined metal oxides, metal hydroxides and/or metal oxide hydrates,where the second of these uncalcined metal oxides, metal hydroxidesand/or metal oxide hydrates is physically different from the others andis of such a nature that it can diffuse into at least one of the otheruncalcined metal oxides, metal hydroxides and/or metal oxide hydrates,and iii) calcining the product obtained in step ii), optionally underreducing conditions, at a temperature from a range from 400° C. to 980°C.

In a very particularly preferred embodiment, the present inventionrelates to an absorbent effect pigment comprising a nonmetallicsubstrate in platelet form, preferably a synthetic mica platelet or aglass platelet, and a coating applied thereto, where the coating has atleast one spacer layer which is essentially parallel to the surface ofthe nonmetallic substrate in platelet form and is of mean height h_(a)from a range from 14 nm to 51 nm, and the effect pigment is obtainableby i) optionally applying an uncalcined tin oxide, tin hydroxide and/ortin oxide hydrate layer using a water-soluble tin(IV) salt to thenonmetallic substrate in platelet form, ii) sequentially applying afirst layer A using a water-soluble iron(III) salt, a second layer Busing a water-soluble tin(IV) salt and/or titanium(IV) salt, a thirdlayer C using a water-soluble iron(III) salt, and iii) calcining theproduct obtained in step ii) at a temperature from a range from 400° C.to 910° C.

In a preferred embodiment, the coating of the absorbent effect pigmentsof the invention, in each case prior to drying and/or calcination,comprises at least one layer of high refractive index composed of orcomprising titanium oxide, titanium hydroxide and/or titanium oxidehydrate and at least two nonadjacent layers of high refractive indexcomposed of or comprising iron oxide, iron hydroxide and/or iron oxidehydrate, where the weight ratio in the effect pigment of titanium toiron is <1, preferably within a range from 0.01 to 0.9 and morepreferably within a range from 0.1 to 0.8.

In a further-preferred embodiment, the coating of the absorbent effectpigments of the invention, in each case prior to drying and/orcalcination, comprises at least one layer of high refractive indexcomposed of or comprising tin oxide, tin hydroxide and/or tin oxidehydrate and at least two layers of high refractive index composed of orcomprising iron oxide, iron hydroxide and/or iron oxide hydrate, wherethe weight ratio in the effect pigment of tin to iron is <1, preferablywithin a range from 0.01 to 0.9 and more preferably within a range from0.1 to 0.8. In this embodiment, it is especially preferable that firstat least one high-refractive index layer of iron oxide, iron hydroxideand/or iron oxide hydrate and then at least one high-refractive indexlayer of tin oxide, tin hydroxide and/or tin oxide hydrate and a furtherhigh-refractive index layer of iron oxide, iron hydroxide and/or ironoxide hydrate are applied directly to the substrate in platelet form ordirectly to the respective uppermost layer close to the substrate. Inaddition, it is also possible, prior to application of the at least onehigh-refractive index layer of iron oxide, iron hydroxide, iron oxidehydrate, to deposit a layer or preliminary coverage with metal oxides,metal hydroxides, metal oxide hydrates, where the metal ion comprises oris a metal ion selected from the group of metals consisting of Sn andSi, directly to the nonmetallic substrate in platelet form or directlyto the respective uppermost layer close to the substrate, where thelayer thickness may be a few nanometers, preferably less than 10 nm,more preferably less than 5 nm and most preferably less than 3 nm, andsaid layer need not fully surround the substrate. The tin oxide, tinhydroxide and/or tin oxide hydrate may be present at least partly in amixed layer with the iron oxide, iron hydroxide and/or iron oxidehydrate.

In a further preferred embodiment, the coating of the absorbent effectpigments of the invention, in each case prior to drying and/orcalcination, comprises at least one high-refractive index layer of ironoxide, iron hydroxide and/or iron oxide hydrate, where at least onefurther layer of tin oxide, tin hydroxide and/or tin oxide hydrate hasbeen applied to this at least one layer in a proportion from a rangefrom 1% by weight to 25% by weight, preferably from a range from 2% byweight to 20% by weight, more preferably from a range from 3% by weightto 16% by weight and most preferably from a range from 4% by weight to13% by weight, based in each case on the absorbent effect pigment.Alternatively, the at least one high-refractive index layer of ironoxide, iron hydroxide and/or iron oxide hydrate may have been doped withMg or Ce. After calcination, iron oxide present in the coating may bepresent in the form of hematite and/or goethite.

In a further embodiment, the present invention relates to an absorbenteffect pigment comprising a nonmetallic substrate in platelet form,preferably a synthetic mica platelet or a glass platelet, and a coatingapplied to the substrate, where the coating has at least one spacerlayer essentially parallel to the surface of the nonmetallic substratein platelet form and the effect pigment has been calcined under reducingconditions or has a semitransparent metal layer in the overall coating,preferably as the outermost layer directly beneath an optionally presentprotective layer.

In one embodiment, the coating of the absorbent effect pigments of theinvention, rather than the at least one metal oxide, metal hydroxideand/or metal oxide hydrate, comprises the corresponding metal suboxides,metal fluorides, metal nitrides, metal oxynitrides, metal oxyhalidesand/or metal sulfides.

In one embodiment, the coating of the absorbent effect pigments of theinvention comprises, in addition to the at least one metal oxide, metalhydroxide and/or metal oxide hydrate, at least one metal suboxide, metalfluoride, metal nitride, metal oxynitride, metal oxyhalide and/or metalsulfide.

There follows an elucidation of the invention by a few examples, but theexamples do not restrict the invention. All % figures in the examplesand comparative examples should be understood as % by weight.

I PRODUCTION OF THE ABSORBENT EFFECT PIGMENTS OF THE INVENTION Example 1

200 g of synthetic mica platelets (fluorphlogopite platelets) having aparticle size distribution according to MALVERN Mastersizer MS 2000:D₁₀=10 μm, D₅₀=22 μm, D₉₀=40 μm were suspended in 1300 mL ofdemineralized water and heated to 85° C. with turbulent stirring. The pHof the suspension was lowered to pH 2.2. By addition of 75 g of a tinchloride solution of concentration c(Sn)=12 g/L, a layer of tin oxidewas deposited on the surface of the glass platelets.

The pH of the suspension was subsequently lowered to pH 1.9 and then asolution of 570 mL of TiCl₄ (200 g of TiO₂/L of demineralized water) wasdosed into the suspension. After the end of the addition, the mixturewas stirred for a further 10 minutes and then the pH was adjusted to pH2.6. Subsequently, 50 mL of an aqueous iron chloride solution having adensity of 1.42 g/cm³ were dosed. On completion of dosage, the mixturewas stirred for another 10 minutes, the pH was adjusted to pH 1.9, and630 mL of a solution of TiCl₄ (200 g of TiO₂/L of demineralized water)were dosed into the suspension.

Thereafter, a further dosage of 40 mL of an aqueous iron chloridesolution having a density of 1.42 g/cm³ was added in after 10 minutes.15 minutes after the addition had ended, the suspension was filtered offand the filtercake was washed. The filtercake was dried and calcined at850° C. for 60 min. Extremely chromatic, high-gloss gold interferingeffect pigments with yellow absorption color and very good hidingcapacity were obtained.

Example 2

The filtercake from example 1 was dried and calcined at 820° C. for 60minutes under a hydrogen atmosphere. Highly chromatic, high-glossgreen/gold interference effect pigments with black absorption color andgood hiding capacity were obtained.

Example 3

200 g of synthetic mica platelets (fluorphlogopite platelets) having aparticle size distribution according to MALVERN Mastersizer MS 2000:D₁₀=10 μm, D₅₀=22 μm, D₉₀=40 μm were suspended in 1300 mL ofdemineralized water and heated to 85° C. with turbulent stirring. The pHof the suspension was lowered to pH 2.2. By addition of 100 g of a tinchloride solution of concentration c(Sn)=12 g/L, a layer of tin oxidewas deposited on the surface of the synthetic mica platelets.

The pH of the suspension was lowered to pH 1.9 and then a solution of400 mL of TiCl₄ (200 g of TiO₂/L of demineralized water) was dosed intothe suspension. After the end of the addition, the mixture was stirredfor a further 10 minutes and then the pH was adjusted to pH 2.6.Subsequently, 30 mL of an aqueous iron chloride solution having adensity of 1.42 g/cm³ were dosed in. On completion of addition, themixture was stirred for another 10 minutes, and 405 mL of a furthersolution of TiCl₄ (200 g of TiO₂/L of demineralized water) were dosedinto the suspension. Thereafter, a further dosage of 40 mL of an aqueousiron chloride solution having a density of 1.42 g/cm³ was added after 10minutes. 15 minutes after the addition had ended, the suspension wasfiltered off and the filtercake was washed. The filtercake was dried andcalcined at 650° C. for 30 minutes under reducing conditions. Highlychromatic, glossy blue interfering effect pigments with gray absorptioncolor were obtained.

Example 4

200 g of glass platelets having a particle size distribution accordingto MALVERN Mastersizer MS 2000: D₁₀=34 μm, D₅₀=57 μm, D₉₀=96 μm weresuspended in 1300 mL of DM water (DM=demineralized) and heated to 85° C.with turbulent stirring. The pH of the suspension was lowered to pH 2.2.By addition of 75 g of a tin chloride solution of concentration c(Sn)=12g/L, a layer of tin oxide was deposited on the surface of the glassplatelets.

Thereafter, the pH was lowered to pH 2.0 with dilute HCl, and then asolution of 148 mL of TiCl₄ (200 g of TiO₂/L of demineralized water) wasdosed into the suspension. After the end of the addition, the mixturewas stirred for a further 10 minutes and then the pH was adjusted to pH2.6. Subsequently, 8 mL of an aqueous iron chloride solution having adensity of 1.25 g/cm³ were dosed in. On completion of dosage, themixture was stirred for another 10 minutes and, by addition of 75 mL oftin chloride solution of concentration c(Sn)=12 g/L, a further thinlayer of tin oxide was deposited on the pigment surface. Subsequently,180 mL of a solution of TiCl₄ (200 g of TiO₂/L of demineralized water)were doesd into the suspension. Thereafter, 20 mL of an aqueous ironchloride solution having a density of 1.25 g/cm³ were dosed in after 10minutes. 15 minutes after the addition, the suspension was filtered offand the filtercake was washed. The filtercake was dried and calcined at750° C. for 60 minutes under reducing conditions. Extremely chromatic,high-gloss gold interfering effect pigments with gray absorption colorwere obtained.

Example 5

200 g of synthetic mica platelets (fluorphlogopite platelets) having aparticle size distribution according to MALVERN Mastersizer MS 2000:D₁₀=10 μm, D₅₀=22 μm, D₉₀=40 μm were suspended in 1300 mL ofdemineralized water and heated to 85° C. with turbulent stirring. The pHof the suspension was lowered to pH 2.6.

Subsequently, 40 mL of an aqueous iron chloride solution having adensity of 1.42 g/cm³ was dosed in. Thereafter, the mixture was stirredfor 10 minutes and, at pH 1.9, 560 mL of a solution of TiCl₄ (200 g ofTiO₂/L of demineralized water) were dosed into the suspension.

After adjusting the pH to the initial value, 40 mL of an aqueous ironchloride solution having a density of 1.42 g/cm³ were then added to thesuspension. Once more, the pH was adjusted to pH 1.9 and 600 mL of asolution of TiCl₄ (200 g of TiO₂/L of demineralized water) were dosedinto the suspension. A further addition of 15 mL of an aqueous ironchloride solution having a density of 1.42 g/cm³ was executed and thenthe mixture was stirred for a further 120 min and filtered. The washedfiltercake was dried and calcined at 800° C. for 45 min. Extremelychromatic, high-gloss gold interfering effect pigments with yellowabsorption color and very good hiding capacity were obtained.

Example 6

200 g of synthetic mica platelets (fluorphlogopite platelets) having aparticle size distribution according to MALVERN Mastersizer MS 2000:D₁₀=10 μm, D₅₀=22 μm, D₉₀=40 μm were suspended in 1300 mL ofdemineralized water and heated to 85° C. with turbulent stirring. The pHof the suspension was adjusted to pH 2.6. By addition of 500 g of anaqueous iron chloride solution having a density of 1.42 g/cm³, a layerof iron oxide was deposited on the surface of the synthetic micaplatelets.

After the end of the addition, the mixture was stirred for a further 120minutes and then the pH was adjusted to pH 2.2. Subsequently, 1000 g ofa tin chloride solution of concentration c(Sn)=12 g/L were dosed in. Oncompletion of dosage, the mixture was stirred for another 120 minutesand then, by addition of 710 g of an aqueous iron chloride solutionhaving a density of 1.42 g/cm³, a further layer of iron oxide wasdeposited on the surface of the synthetic mica platelets. 60 minutesafter the addition had ended, the suspension was filtered off and thefiltercake was washed. The filtercake was dried if appropriate andcalcined at 800° C. for 60 minutes under reducing conditions. Extremelychromatic, high-gloss red interfering effect pigments with redabsorption color and with very good hiding power were obtained.

Example 7

200 g of synthetic mica platelets (fluorphlogopite platelets) having aparticle size distribution according to MALVERN Mastersizer MS 2000:D₁₀=10 μm, D₅₀=22 μm, D₉₀=40 μm were suspended in 1300 mL ofdemineralized water and heated to 85° C. with turbulent stirring. The pHof the suspension was adjusted to pH 2.2. By addition of 100 g of a tinchloride solution of concentration c(Sn)=12 g/L, a layer of tin oxidewas deposited on the surface of the synthetic mica platelets.

The pH of the suspension was lowered thereafter to pH 1.9 and then asolution of 400 mL of TiCl₄ (200 g of TiO₂/L of demineralized water) wasdosed into the suspension. After the end of the addition, the mixturewas stirred for a further 10 minutes and then the pH was adjusted to pH2.2. Subsequently, 150 mL of a 20% by weight aqueous zirconium chloridesolution were dosed in. On completion of metered addition, the mixturewas stirred for a further 40 minutes, and 300 mL of TiCl₄ (200 g ofTiO₂/L of demineralized water) were dosed into the suspension. After theaddition had ended, the suspension was filtered off and the filtercakewas washed. The filtercake was dried and calcined at 800° C. for 60minutes under reducing conditions. Highly chromatic, highly glossy blueinterfering effect pigments with gray absorption color were obtained.

Example 8

15 g of pigment from example 6 were suspended in 450 mL of demineralizedwater. Thereafter, 30 mL of silver salt solution consisting of 50 g ofAgNO₃ and 50 mL of 28% by weight ammonia solution were supplemented upto 1 L with demineralized water, and the suspension was addedsimultaneously and stirred at room temperature for 5 minutes.Subsequently, 9 mL of a 35% by weight formaldehyde solution were addedand the mixture was stirred for a further 1 hour. The suspension wasthen filtered and the pigment cake was dried at 120° C. under reducedpressure.

Dark blue interfering effect pigments with black absorption color and asilver content of 11.1% were obtained.

Example 9

100 g of the effect pigment obtained from example 1 were suspended in850 mL of demineralized water and heated to 85° C. with turbulentstirring. The pH was lowered to pH 4.2 with dilute hydrochloric acid.Then a solution of 0.93 g of Ce(NO₃)₃×6 H₂O dissolved in 40 mL ofdemineralized water was metered in. At the same time, the pH was keptconstant by dropwise addition of a 10% NaOH solution. Once the solutionhad been added completely, the mixture was stirred for a further hourand the pH was adjusted thereafter to pH 10 with dilute sodium hydroxidesolution. Thereafter, 5.7 g of Dynasylan 1146 diluted with 24.3 g ofdemineralized water were added to the suspension, the suspension wasstirred for another 180 minutes and filtered, and the filtercake waswashed with demineralized water. The filtercake was dried at 95° C.under reduced pressure.

Example 10

200 g of synthetic mica platelets (fluorphlogopite platelets) having aparticle size distribution according to MALVERN Mastersizer MS 2000:D₁₀=10 μm, D₅₀=22 μm, D₉₀=40 μm were suspended in 1300 mL ofdemineralized water and heated to 85° C. with turbulent stirring. The pHof the suspension was adjusted to pH 2.6. By addition of 570 g of anaqueous iron chloride solution having a density of 1.42 g/cm³, a layerof iron oxide was deposited on the surface of the synthetic micaplatelets.

The pH of the suspension was lowered thereafter to pH 1.9 and then asolution of 250 mL of TiCl₄ (200 g of TiO₂/L of demineralized water) wasdosed into the suspension.

Thereafter, the mixture was stirred for another 120 minutes and then, byaddition of 600 g of an aqueous iron chloride solution having a densityof 1.42 g/cm³, a further layer of iron oxide was deposited on thesurface of the synthetic mica platelets. 60 minutes after the additionhad ended, the suspension was filtered off and the filtercake waswashed. The filtercake was dried if necessary and calcined at 400° C.for 60 minutes. Extremely chromatic, high-gloss red interfering effectpigments with red absorption color and very good hiding power wereobtained.

Example 11

100 g of the effect pigment obtained from example 6 were suspended in850 mL of demineralized water and heated to 85° C. with turbulentstirring. The pH was lowered to pH 4.2 with dilute hydrochloric acid.Then a solution of 0.93 g of Ce(NO₃)₃×6 H₂O dissolved in 40 mL ofdemineralized water was dosed in. At the same time, the pH was keptconstant by dropwise addition of a 10% NaOH solution. Once the solutionhad been added completely, the mixture was stirred for a further hourand the pH was adjusted thereafter to pH 10 with dilute sodium hydroxidesolution. Thereafter, 5.7 g of Dynasylan 1146 diluted with 24.3 g ofdemineralized water were added to the suspension, the suspension wasstirred for another 180 minutes and filtered, and the filtercake waswashed with demineralized water. The filtercake was dried at 95° C.under reduced pressure.

Example 12

300 g of glass platelets having a particle size distribution accordingto MALVERN Mastersizer MS 2000: D₁₀=10 μm, D₅₀=20 μm, D₉₀=40 μm weresuspended in 1500 mL of demineralized water and heated to 85° C. withturbulent stirring. The pH of the suspension was lowered to pH 2.2. Byaddition of 70 mL of a tin chloride solution of concentration c(Sn)=12g/L, a layer of tin oxide was deposited on the surface of the glassplatelets. Thereafter, the pH was lowered to pH 2.0 with dilute HCl, andthen a solution of 250 mL of TiCl₄ (200 g of TiO₂/L of demineralizedwater) was dosed into the suspension. After the end of the addition, themixture was stirred for a further 10 minutes and then the pH wasadjusted to pH 2.6. Subsequently, 100 mL of an aqueous iron chloridesolution having a density of 1.25 g/cm³ were dosed in. Subsequently, 300mL of a solution of TiCl₄ (200 g of TiO₂/L of demineralized water) weredosed into the suspension. 15 minutes after completion of addition, thesuspension was filtered off and the filtercake was washed. Thefiltercake was dried and calcined at 760° C. for 60 minutes. Extremelychromatic, high-gloss golden effect pigments were obtained.

Comparative Example 1

200 g of synthetic mica platelets (fluorphlogopite platelets) having aparticle size distribution according to MALVERN Mastersizer MS 2000:D₁₀=25 μm, D₅₀=55 μm, D₅₀=100 μm, span ΔD=1.36 were suspended in 1300 mLof DM water (DM=demineralized) and heated to 85° C. with stirring. ThepH of the suspension was lowered to pH 2.2. By addition of 100 g of atin chloride solution of concentration c(Sn)=12 g/L, a layer of “SnO₂”was deposited on the surface of the synthetic mica platelets.Thereafter, the pH was lowered to pH 1.9 with dilute HCl, and then asolution of 500 mL of TiCl₄ (200 g of TiO₂/L of demineralized water) wasmetered into the suspension. After the end of the addition, the mixturewas stirred for a further 10 minutes and then the pH were adjusted to pH2.6. Subsequently, 60 mL of an aqueous iron chloride solution having adensity of 1.42 g/cm³ was metered in. 15 minutes after completion ofaddition, the suspension was filtered off and the filtercake was washed.The filtercake was dried and calcined at 700° C. for 60 minutes underreducing conditions. Shiny gold pigments with dark absorption color wereobtained.

Comparative Example 2

Red effect pigment based on natural mica platelets, coated with ironoxide, Iriodin 504 Red, from Merck.

Comparative Example 3

Red effect pigment based on SiO₂ platelets, coated with iron oxide,Iriodin 4504 Lava Red, from Merck.

II CHARACTERIZATION OF THE ABSORBENT EFFECT PIGMENTS AND PIGMENTS FROMTHE COMPARATIVE EXAMPLES IIa Particle Size Measurement

The size distribution curve of the absorbent effect pigments of theinvention and of the pigments from the comparative examples wasdetermined using the Malvern Mastersizer 2000 instrument according tothe manufacturer's instructions. For this purpose, about 0.1 g of therespective pigment was introduced into the sample preparation cell ofthe measuring instrument by means of a Pasteur pipette as an aqueoussolution, without addition of dispersing aids, with constant stirring,and analyzed repeatedly. The individual measurement results were used toform the medians. The scattered light signals were evaluated by theFraunhofer method.

The median particle size D₅₀ in the context of this invention isunderstood to mean the D₅₀ of the cumulative frequency distribution ofthe volume-averaged size distribution function, as obtained by laserdiffraction methods. The D₅₀ indicates that 50% of the pigments have adiameter equal to or less than the value reported, for example 20 μm.Correspondingly, the D₁₀ and D₉₀ respectively state that 10% and 90% ofthe pigments have a diameter equal to or less than the respectivemeasured value. The span ΔD, defined as ΔD=D₉₀-D₁₀/D₅₀, indicates thebreadth of the particle size distribution. With regard to the visualappearance of the absorbent effect pigments of the invention, a smallvalue of ΔD, i.e. a narrow span, is preferred.

TABLE 2 Particle sizes Example/ D₁₀ D₅₀ D₉₀ comparative example [μm][μm] [μm] Span Example 1 10.8 22.5 40.6 1.326 Example 2 11.0 22.8 40.81.307 Example 3 12.4 23.7 42.1 1.254 Example 4 28.1 53.0 92.7 1.219Example 5 11.9 22.9 40.9 1.271 Example 6 12.5 23.0 40.4 1.217 Example 711.9 22.4 39.9 1.247 Example 8 13.7 24.3 41.3 1.138 Example 9 11.1 22.640.8 1.314 Example 10 8.8 20.1 37.6 1.429 Example 12 9.7 21.3 41.3 1.482Comparative example 1 12.0 22.9 40.8 1.260 Comparative example 2 10.821.9 41.5 1.402 Comparative example 3 9.7 19.3 35.5 1.337

IIb Angle-Dependent Color Measurements

To measure the color and brightness values, the effect pigments of theinvention and the pigments from the comparative examples were stirredinto a conventional nitrocellulose lacquer (Erco 2615e bronze mixinglacquer colorless; from Maeder Plastiklack AG) at a pigmentation levelof 6% by weight, based on the total weight of the wet lacquer. This wasdone by initially charging the respective pigments and then dispersingthem into the lacquer with a brush. The finished lacquer was applied toblack/white hiding charts (Byko-Chart 2853, from Byk-Gardner) in a wetfilm thickness of 40 μm or of 76 μm (example 4) with a spiral applicatoron an applicator drawdown apparatus (RK Print Coat Instr. Ltd. Citenco K101 drawdown apparatus), and subsequently dried at room temperature. Thechoice of spiral applicator is made according to table A depending onthe D₅₀ of the pigments or substrates to be applied in each case.

The BYK-mac multi-angle colorimeter (from Byk-Gardner) was used todetermine the color values on the black background of the hiding chartat a constant angle of incidence of 45° (according to the manufacturer'sinstructions) at various observation angles relative to the specularangle. Characterization of the color intensity was accomplished usingthe chroma value C*15, which was measured at a measurement angleseparated by 15° from the specular angle on the black background of theblack/white hiding chart.

Strongly reflecting samples (mirrors in the ideal case) reflectvirtually all the incident light at what is called the specular angle.The closer to the specular angle the measurement is made on the lacquerapplication, the more intense the appearance of the interference color.

TABLE A Wet film thickness as a function of the D₅₀ of the pigments orsubstrates to be applied Spiral D₅₀ applicator <40 μm 40 μm 40 μm-85 μm76 μm >85 μm 100 μm 

TABLE 3 Color and brightness values of gold effect pigments Example/ NClacquer 6% 40 μm BykMac comparative L 110° a*15° b*15° C* 15° example s¹s s s Example 1 91.7 −7.1 46.1 46.6 Example 2 84.3 −6.6 35.1 35.7Example 4 77.4 −10.6 23.3 25.6 Example 5 90.8 −10.9 38.6 40.1 Example 992.4 −4.0 48.3 48.5 Example 12 73.74 −3.50 32.84 33.02 Comparative 83.91.0 25.3 25.3 example 1

TABLE 4 Color and brightness values of red effect pigments Example/ NClacquer 6% 40 μm BykMac comparative L 15° a*15° b*15° C* 15° example s¹s s s Example 6 57.8 42.3 26.8 50.0 Example 7 72.9 16.6 −29.6 34.0Example 10 64.2 40.2 27.6 48.8 Comparative 74.5 38.6 11.4 40.2 example 2¹Measured on the black background of the black/white hiding chart.

Table 3 indicates the color values for gold interference effectpigments. It is clear from this that the color intensity of the effectpigments of the invention is much higher than the color intensity of thesingle-layer pearlescent pigment from comparative example 1. Anexception to this is example 4, since this involves a much thicker glasssubstrate.

The color values for red interference effect pigments that are listed intable 4 for the inventive examples are also well above those ofcomparative example 2.

IIc Comparison of Hiding

To determine the hiding quotient D_(q), defined as

${D_{q} = \frac{L_{black}^{*25}}{L_{white}^{*25}}},$the brightness values L*25° of the lacquer applications from IIb wererecorded with the BYK-mac multi-angle colorimeter (from Byk-Gardner) ata measurement angle of 25° on the black and white backgrounds of theblack/white hiding chart. The 25° measurement geometry, at a constantangle of incidence of 45°, relates to the difference from the specularangle. The viewing angle is measured away from the specular reflectionin the plane of illumination.

The effect pigments of the invention have good hiding power. The hidingquotient D_(q) thereof is preferably ≥0.41. The hiding quotient D_(q) ofthe inventive absorbent effect pigments in platelet form from examples 1to 10, as can be inferred from table 5, is in each case well above 0.41.

IId Gloss Measurements

Gloss is a measure of directed reflection. To determine the gloss, thepaint applications from IIb on the white background of the black/whitehiding chart were analyzed at a measurement angle of 60° based on thevertical with the aid of a Micro-Tri-Gloss gloss meter from Byk-Gardner.The gloss values of the absorbent effect pigments of the invention andof the pigments from the comparative examples are listed in table 5.

Some of the inventive absorbent effect pigments in platelet form fromexamples 1 to 10 show distinctly higher gloss values than the pigmentshaving a single-layer coating from comparative examples 2 and 3.

The gloss measurements from table 5 confirm the very high reflectivityof the pigments of the invention compared to the prior art.

IIe Effect Measurements

In order to objectively describe the optical effect of the absorbenteffect pigments of the invention, effect measurements were conductedwith the BYK-mac spectrophotometer (from Byk-Gardner) using the lacquerapplications from IIb (cf. Byk-Gardner catalog “Qualitätskontrolle fürLacke and Kunststoffe” [Quality Control for Lacquers and Adhesives],2011/2012, p. 97/98). The corresponding measurement values for thesparkle intensity S_i, the sparkle area S_a and the graininess G arecollected in table 5.

TABLE 5 Effect measurements, hiding quotient and gloss values Example/comparative S_i 15° S_a 15° G 60° gloss example (s)¹ (s)¹ (s)¹ D_(q) 25°(w)² Example 1 15.44 33.99 9.99 0.607 85.8 Example 2 12.75 33.59 8.590.618 70.5 Example 3 6.14 24.72 4.66 0.495 42.3 Example 4 53.95 33.6613.85 0.522 81.5 Example 5 10.15 32.00 8.15 0.692 49.9 Example 6 6.1630.01 4.37 0.558 52.6 Example 7 5.62 24.12 5.60 0.440 40.3 Example 87.84 33.93 4.04 0.505 48.8 Example 9 14.58 33.75 9.98 0.630 90.8 Example10 6.35 27.85 4.68 0.505 53.9 Example 12 51.65 34.71 13.17 0.4760 69.1Comparative 4.70 19.38 4.15 0.661 41.8 example 2 Comparative 4.28 18.573.45 0.719 32.3 example 3 ¹Measured on the black background of theblack/white hiding chart. ²Measured on the white background of theblack/white hiding chart.

The effect values S_i, S_a and G of the inventive absorbent effectpigments in platelet form from examples 1 to 10 and 12 are higher thanthe values for comparative examples 2 and 3. The achievable opticaleffects of the inventive absorbent effect pigments in platelet form aremuch more marked than in the case of conventional effect pigments with asingle-layer coating from comparative examples 2 and 3.

IIf Waring Blender

In industry, many lacquers are processed in circulation systems. In thiscase, the lacquer components are subjected to high shear forces. TheWaring blender test simulates these conditions and serves for assessmentof the ring line stability/shear stability. Specifically pigmentswherein the coating has not been adequately anchored on the supportmaterial exhibit significant deviations in the chroma values in thistest compared to the untreated applications. The Waring blender test canthus be regarded as a measure of the mutual adhesion of the pigmentcoating with respect to shear forces.

For this purpose, the absorbent effect pigments of the invention or thepigments from the comparative examples were weighed out according to therecipe below and converted stepwise to a paste with a conventionalacrylic lacquer in an 880 mL beaker. Thereafter, the viscosity wasadjusted with butyl acetate/xylene 1:1 to 17″ in the DIN 4 mm cup. Atotal of 600 g of lacquer were produced, of which 400 g were introducedinto a jacketed water-cooled 1 kg vessel and stirred with a specificattachment under the Dispermat (from Waring Blenders). The stirring timewas 8 minutes at 13 500 rpm, then 200 g of lacquer were removed and therest was stirred for a further 12 minutes.

Recipe: 6% pigment

-   -   8% butyl acetate 85    -   86% acrylic lacquer, colorless    -   30% dilution butyl acetate 85/xylene 1:1        200 g each of the untreated and treated lacquers were applied to        a test sheet with a spraying machine and the Sata LP-90 spray        gun according to the following settings:        Setting: Needle: 1.3.4    -   Pressure: 4 bar        Runs: The number of spray runs was chosen such that there was a        dry lacquer layer thickness of 15-20 μm.

Conventionally, effect pigments are regarded as being shear-stable whenthe gloss differential and the color differential, measured close to thespecular angle, is relatively low in the application after the Waringblender test. The ΔC* 15° value relative to the untreated sample shouldideally be less than 2. Table 6 shows the change in color ΔC* 15° andthe change in gloss Δ60° gloss of the sample that has been subjected tothe Waring blender test relative to the untreated sample for inventiveexamples 5 and 10.

TABLE 6 Gloss differential and color differential in the Waring blendertest ΔC* (15°) Δgloss (60°) Example 5 0.9 −1.3 Example 10 1.3 −0.8

The absorbent effect pigments of the invention from examples 5 and 10fulfill the criteria of the test. The color difference is negligiblysmall. Even under the microscope, it was barely possible to detect anychanges such as flaking of the coating or other surface defects thathave arisen.

The absorbent effect pigments of the invention are found to be extremelyshear-stable in spite of their spacer layer.

IIg Determination of Chemical Stability

The chemical stability of the absorbent effect pigments of the inventionand of the pigments from the comparative examples was determined withreference to applications of lacquer to plastic panels. 6 g of therespective pigment were stirred into a mixture of 90 g of a conventionalcolorless acrylic lacquer and 10 g of butyl acetate 85. Thereafter, theviscosity was adjusted with a mixture of butyl acetate 85 and xylene ina ratio of 1:1 to 17″ in the DIN 4 mm cup.

100 g of this lacquer in each case were applied to the panels in hidingapplication analogously to IIf with a spraying machine. After thecoating, the panels were baked at 80° C. for 30 minutes. 24 hours later,the panels were immersed to half their height into 10% sodium hydroxidesolution. After a contact time of 7 days, the panels were rinsed withdemineralized water and then, after drying time of 2 hours, assessedvisually for damage and/or discoloration. In addition, discoloration wasanalyzed with the aid of the BYK-mac (from Byk-Gardner). The change incolor was characterized using the ΔE value of the exposed sample versusthe corresponding unexposed sample at a measurement angle of 15°. Theresults are shown in table 7 below.

TABLE 7 Color change ΔE Example/comparative example ΔE(15°) Example 102.40 Comparative example 3 13.31

Pigments with ΔE(15°)<3 can be regarded as stable to chemicals. Theabsorbent effect pigments of the invention from example 10 are below thelimit, while the pigments from comparative example 3 distinctly exceedit.

IIh X-Ray Fluorescence Analysis (XRF)

The metal oxide, metal hydroxide and/or metal oxide hydrate contents ofthe absorbent effect pigments of the invention and of the pigments fromthe comparative examples were determined by means of x-ray fluorescenceanalysis (XRF). For this purpose, the respective pigments wereincorporated into a lithium tetraborate glass tablet, fixed in solidsample measuring cups and analyzed therefrom. The measuring instrumentused was the Advantix ARL system from Thermo Scientific. Themeasurements are shown in table 8. The figures for the differentcontents are reported here as TiO₂ for titanium, as Fe₂O₃ for iron, andas SnO₂ for tin.

TABLE 8 Mean height h_(a) of the spacer layer and XRF values Example/SEM XRF (as oxide) comparative example Mean height h_(a) [nm] Ti[%]Fe[%] Sn[%] Example 1 30 57.7 6.9 0.78 Example 2 28 57.7 6.9 0.78Example 3 20 47.2 5.8 0.55 Example 4 25 28.6 3.1 0.98 Example 5 38 54.910.6  / Example 6 55 / 65.8  4.3  Example 7 51 48.2  0.04 3.1  Example 8/ / / / Example 10 20  9.1 51.1  / Example 12 20 23.9 4.6 1.26Comparative example 1 no spacer layer / / / Comparative example 2 nospacer layer / / / Comparative example 3 no spacer layer / / /

III CONDENSATE WATER TEST

To determine condensate water stability, the absorbent effect pigmentsof the invention and the pigments from the comparative examples wereincorporated into a waterborne lacquer system and the test applicationswere produced by spray painting onto aluminum sheets. The basecoat wasovercoated with a conventional one-component clearcoat and then baked.These applications were tested according to DIN 50 017 (watercondensation-constant atmospheres). Bond strength was tested by means ofcross-cutting according to DIN EN ISO 2409 immediately after the end ofthe test by comparison with the unexposed sample. In this context, Cc 0means no change and Cc 5 a very significant change.

The swelling characteristics were visually assessed immediately aftercondensate water exposure in accordance with DIN 53230. In this context,the index 0 means no change and the index 5 a very significant change.

Finally, the DOI (distinctness of image) was determined with the aid ofa Wave-scan II from Byk-Gardner.

TABLE 9 Condensate water results 20° 20° gloss gloss Loss Cross- beforeafter of cutting Swelling Sample CW test CW test gloss DOI immediatevisual Example 9 90.3 89.7 <1% 78.2 0 0 Example 11 92.8 90.6 2.4%  80.11 0 Comparative 91.2 21.7 76% n.d. 5 4 example 2

The pigment from comparative example 2 had significant swellingcharacteristics and poor interlayer adhesion. The DOI was no longermeasurable because of the high degree of fine structure after condensatewater exposure.

The absorbent effect pigments of the invention from examples 9 and 11,by contrast, were found to be stable and exhibited virtually no changesbefore and after the test.

IIj UV Stability

The UV stability of the absorbent effect pigments of the invention andof the pigments from the comparative examples was determined inaccordance with the quick UV test described in EP 0 870 730 A1 fordetermination of the photochemical UV activity of TiO₂ pigments. Forthis purpose, 1.0 g of the corresponding pigment were dispersed into 9.0g of a double bond-rich melamine-containing lacquer. Applicatordrawdowns on white cardboard were produced and dried at roomtemperature. The applicator drawdowns were divided and one of the twosections of each was stored in the dark as an unexposed comparativespecimen. Subsequently, the samples were irradiated with UV-containinglight (UVA-340 lamp, irradiation intensity 1.0 W/m²/nm) in a QUV systemfrom Q-Panel for 150 minutes. Immediately after the end of the test, aMinolta CM-508i colorimeter was used to determine color values for theexposed samples relative to the respective reference sample. Theresulting ΔE* values, calculated according to the Hunter L*a*b* formula,are shown in table 9.

In this test, essentially a gray/blue color of the TiO₂ layer of therespective pigment is observed owing to Ti(III) species formed under UVlight. A condition for this is that the electron hole has left theenvironment of the TiO₂ and cannot recombine directly with the remainingelectron again—for instance through reaction with olefinic double bondsof the binder. Since a melamine-containing lacquer layer significantlyslows the diffusion of water (vapor) and oxygen to the pigment surface,reoxidation of the titanium(III) species takes place at a significantlyretarded rate, and so the graying can be measured and the ΔE* value canbe used as a measure for the UV stability of the pigments. A relativelylarge numerical ΔE* value of the exposed sample relative to theunexposed reference sample thus means relatively low UV stability of thepigment examined.

TABLE 10 UV test results Example/ comparative example ΔE* Example 5 3.23Example 10 2.96 Comparative example 1 7.28

The comparative example had a much greater change in color (ΔE*) aftercorresponding exposure.

IIk Determination of the Mean Thickness of the Nonmetallic Substrates inPlatelet Form, the Mean Layer Thickness of Layers 2 and 3, the MeanLayer Thickness of the Overall Coating, the Mean Height h_(a) of theSpacer Layer and the Mean Height h_(H) of the Cavities

For this purpose, the absorbent effect pigments of the invention wereincorporated in a concentration of 10% into a two-component clearcoat,Autoclear Plus HS from Sikkens GmbH, with a sleeved brush, applied to afilm with the aid of a spiral applicator (wet film thickness 26 μm) anddried. After a drying time of 24 h, transverse sections of theseapplicator drawdowns were produced. The transverse sections wereanalyzed by SEM, with analysis of at least 100 individual pigments to bestatistically meaningful for determination of the mean thickness of thenonmetallic substrates in platelet form. To determine the mean layerthickness of layers 2 and 3, the mean thickness of the overall coating,the mean height h_(a) of the spacer layer and the mean height h_(H) ofthe cavities, the upper and lower substrate surfaces, i.e. the longerside of the nonmetallic substrate in platelet form recognizable in eachcase in the SEM transverse section, were each used as the baseline. Thebaseline was drawn here along the surface of the substrate in plateletform in the scanning electron micrograph of the transverse section byconnecting the two points of intersection of nonmetallic substrate inplatelet form—optional layer 1 or of nonmetallic substrate in plateletform—layer 2 from the left- and right-hand edges of the scanningelectron micrograph of the transverse section to one another by means ofa straight line. The scanning electron micrographs of transverse imageswere analyzed with the aid of the AxioVision 4.6.3 image processingsoftware (from Zeiss).

A sufficient number of parallel lines were drawn at 50 nm intervals at a90° angle from these two baselines as to place a grid over the completescanning electron micrograph of the transverse section of the effectpigment (FIG. 4). The magnification of the scanning electron micrographof the transverse section was preferably at least 50 000-fold, based onPolaroid 545. Proceeding from the respective upper and lower baselinesof the nonmetallic substrate in platelet form in the direction of layer3 in each case, the distances between the points of intersection ofthese lines at the respective interfaces of the optional layer 1 withlayer 2, of layer 2 with the spacer layer, of spacer layer with layer 3and of layer 3 with the environment were measured manually. It happenedhere that a line marked at 50 nm intervals was located directly above aconnection point or a spacer. In this case, only the respective point ofintersection at the interface of line 3 with the environment wasrecorded. These measurements yielded the layer thicknesses of layers 2and 3, the thickness of the overall coating, and the height h_(a) of thespacer layer by formation of differences.

For the determination of the mean height h_(H) of the cavities, thepoints of intersection of these parallel lines with the upper and lowercavity boundaries within the spacer layer were used.

The individual values of the layer thicknesses, the height h_(a) and theheight h_(H) that have been determined in this way were used to form therespective arithmetic means in order to determine the above-specifiedvalues for the mean layer thicknesses, the mean height h_(H) and themean height h_(a). To be statistically meaningful, the above-describedmeasurements were conducted on at least 100 lines. The term “mean” inall cases means the arithmetic mean.

Transverse sections of the pigments from the comparative examples thatdo not have a spacer layer but may have statistically distributed poreswithin the coating were likewise examined by the method described aboveusing scanning electron micrographs of transverse sections. In thiscase, if one of the parallel lines occurred above one or more pores, theheight of the pore(s), the pore midpoint(s) thereof and the distance ofthe pore midpoint(s) from the substrate surface were determined.

As an alternative to transverse sections, the absorbent effect pigmentsof the invention can be cut by means of the FIB method (FIB=focused ionbeam). For this purpose, a fine beam of highly accelerated ions (forexample gallium, xenon, neon or helium) is focused to a point by meansof ion optics and guided line by line over the effect pigment surface tobe processed. On impact with the effect pigment surface, the ionsrelease most of their energy and destroy the coating at this point,which leads to removal of material line by line. It is also possibleusing the scanning electron micrographs that have then been recorded, bythe method described above, to determine the mean height h_(a), the meanlayer thickness of layers 2 and 3 and the mean layer thickness of theoverall coating. The mean thickness of the nonmetallic substrate inplatelet form can also be determined using scanning electron micrographsof the effect pigments that have been cut by the FIB method.

The advantages of the absorbent effect pigments of the invention aretherefore apparent in the sum total of various properties. The absorbenteffect pigments of the invention have high transparency, very goodmechanical and chemical stability, and high gloss and color intensity.None of the comparative pigments considered overall has all theproperties mentioned in a satisfactory manner.

TABLE 11 Characterization of the coating Example/ d_(S2) d_(S3) h_(ma)σh_(Rma) S_(D) A_(H) comparative example [nm] [nm] d_(S2)/d_(S3) [nm]h_(Rma) [%] n_(S) [%] [%] Example 1 85 91 0.94 100.4 0.49 3.8 1.1 5.494.6 Example 3 66 65 1.02 76.3 0.50 5.1 4.6 16.4 83.6 Example 5 83 1050.79 94.7 0.52 4.9 3.2 15.9 84.1 Example 6 70 99 0.71 87.6 0.44 6.5 2.211.0 89.0 Example 7 55 57 0.96 62.0 0.49 13.5 3.6 18.1 81.9 Example 10118 82 1.43 128.3 0.58 4.5 6.2 30.9 69.1 Example 12 100 118 0.85 1100.46 4.9 2.2 11.1 88.9 Comparative example 1 no spacer layer 21.3 1890.0 10.0 Comparative example 2 no spacer layer 24.7 13 65.0 35.0 d_(S2)[nm] = mean layer thickness of layer 2 d_(S3) [nm] = mean layerthickness of layer 3 n_(S) = mean number of bars per μm A_(H) [%] = areaproportion of cavities S_(D) = network density [%] h_(ma) = midpoint ofthe spacer layer (sum total of the layer thickness of the optional layer1 and of layer 2 and half the height h_(a)) h_(Rma) = relative height ofthe spacer layer σh_(Rma) [%] = standard deviation of the relativeheight of the spacer layer

Table 8 shows the mean height h_(a) of the spacer layer of the pigmentsexamined. All the absorbent effect pigments of the invention, bycontrast with the pigments from comparative examples 1 to 3, have aspacer layer.

The pigments from comparative examples 1 and 2 do not have a spacerlayer, but have a statistical distribution of pores within the coating.In table 11, for comparative examples 1 and 2, the value in the σh_(Rma)[%] column means the standard deviation of the pore midpoints from thesubstrate surface. Since the pigment from comparative example 2,however, contains only few statistically distributed pores, the networkdensity SD is 65.0%. The standard deviation of the pore midpoints fromthe substrate surface is 24.7%, which demonstrates that the pores arestatistically distributed within the overall coating. The situation isdifferent for the absorbent effect pigments of the invention fromexamples 1, 3, 5 to 7 and 10. Here, the standard deviation of therelative height of the midpoint of the spacer layer h_(Rma) is <14% ineach case, which indicates that the respective spacer layer thereof isat a defined position within the coating. The standard deviation of thedistances of the pore midpoints from the substrate surface of thepigment from comparative examples 1 and 2 can thus be compared with thestandard deviation of the relative height of the midpoint of the spacerlayer of the absorbent effect pigments of the invention.

IIl Scanning Electron Micrographs

The scanning electron micrographs were obtained using transversesections of the absorbent effect pigments of the invention with theSupra 35 scanning electron microscope (from Zeiss). Energy-dispersivex-ray micro-analysis (EDX analysis) was conducted with the EDAX Sapphireinstrument, from EDAX.

III APPLICATION EXAMPLES Application Example 1: Body Lotion

% by Manufacturer/ INCI name Product name wt. supplier Phase A 85.80Effect pigment from 0.20 example 1 Aqua Water Glycerin Glycerin 85% 2.00H. Erhard Wagner Xanthan Gum Keltrol CG-T 0.60 CP Kelco Phase BIsopropyl Palmitate Isopropyl palmitate 3.00 H. Erhard Wagner GlycerylStearate Aldo MS K FG 2.00 Lonza Cocos Nuifera Oil Ewanol KR 2.00 H.Erhard Wagner Cetearyl Alcohol Tego Alkanol 1618 2.00 Evonik DimethiconeElement 14 PDMS 1.00 Momentive Sodium Polyacrylate Cosmedia SP 0.50 BASFPhase C Phenoxyethanol, Euxyl PE 9010 0.80 Schülke & MeyrEthylhexylglycerin Fragrance Vitamin Bomb 0.10 Bell Europe

The effect pigment from example 1 can be used within a range from 0.1%to 2.5% by weight, based on the total weight of the body lotionformulation. Compensation to 100% by weight of the formulation can beeffected with water.

Keltrol CG-T was dispersed in phase A and heated to 75° C. Phase B washeated separately to 75° C. Subsequently, phase B was added gradually tophase A. The emulsion was cooled down to room temperature while stirringand phase C was added individually.

Application Example 2: Eyeshadow Cream

% by Manufacturer/ INCI name Product name wt. supplier Phase AMicrocrystalline Wax TeCero-Wax 1030 K 4.50 Tromm Wachs CoperniciaCerifera Cera LT 124 carnauba 4.50 Tromm Wachs wax IsohexadecaneIsohexadecane 21.00 Ineos Cyclopentasiloxane, Belsil RG 100 8.00 WackerDimethicone/Vinyltrimethylsiloxysilicate Silicone Elastomer CrosspolymerResin Gel Trimethylsiloxyphenyl Dimethicone Belsil PDM 20 6.00 WackerDimethicone Belsil DM 100 14.00 Wacker Caprylic/Capric TriglycerideMiglyol 812 7.00 Sasol Cyclomethicone (and) Quaternium-90 TixogelVSP-1438 5.00 BYK Bentonite (and) Propylene Carbonate Phase B Effectpigment from 30.00 example 3

The effect pigment from example 3 can be used within a range from 5% to30.0% by weight, based on the total weight of the eyeshadow formulation.Compensation to 100% by weight of the formulation can be effected withisohexadecane.

Phase A was mixed and heated to 85° C., then phase B was added to phaseA while stirring. After dispensing into an appropriate container, themixture is cooled to room temperature.

Application Example 3: Shower Gel

% by Manufacturer/ INCI name Product name wt. supplier Phase A Effectpigment from 0.10 example 5 Aqua Water 58.50 Acrylates CopolymerCarbopol Aqua SF-1 5.50 Lubrizol Phase B Sodium Hydroxide NaOH (10% bywt.) 1.50 Phase C Sodium Laureth Sulfate Zetesol NL-2 U 22.00 Zschimmer& Schwarz Cocamidopropyl Betaine Amphotensid B5 6.00 Zschimmer & SchwarzPEG-7 Glyceryl Cocoate Emanon HE 2.00 Kao Corp. Disodium LaurethSulfosuccinate Sectacin 103 Spezial 2.00 Zschimmmer & Schwarz Phase DPhenoxyethanol (and) Piroctone Nipaguard PO 5 0.60 Clariant OlamineFragrance Water Lily OA 0.20 Bell Flavors and Fragrances Sodium ChlorideSodium Chloride 1.60 VWR

The effect pigment from example 5 can be used within a range from 0.01%to 1.0% by weight, based on the total weight of the shower gelformulation. Compensation to 100% by weight of the formulation can beeffected with water.

Phase A was stirred, then phase B was added and stirred until ahomogeneous appearance was achieved. Phase C was weighed out separately,mixed briefly and added to phase AB. Subsequently, the mixture wasstirred again and phase D was added individually.

Application Example 4: Eyeshadow Compact

% by Manufacturer/ INCI name Product name wt. supplier Phase A Talc TalcPowder 36.00 VWR Bentonite Optigel CK-PC 5.00 BYK Synthetic Synafil S1050 13.00 ECKART Fluorphlogopite Aluminium Starch Agenaflo OS 905110.00 Agrana Octenylsuccinate Magnesium Stearate Magnesium Stearate 6.00VWR Effect pigment from 20.00 example 8 Phase B Cyclomethicone XiameterPMX-0345 5.00 Dow Corning Octyldodecyl Ceraphyl 847 5.00 AshlandStearoyl Stearate

The effect pigment from example 8 can be used within a range from 5.0%to 40.0% by weight, based on the total weight of the eyeshadowformulation. Compensation to 100% by weight of the formulation can beeffected with talc.

Phase A was mixed in a high-speed mixer at 2500 rpm for 30 s.Subsequently, phase B was added and the mixture was mixed in the samemixer at 3000 rpm for 60 s. Finally, the powder mixture was pressed intoshape by means of an eyeshadow press at 100 bar for 30 seconds.

Application Example 5: Mascara

% by Manufacturer/ INCI name Product name wt. supplier Phase A AquaWater 73.00 Bentonite (and) Xanthan Gum Optigel WX-PC 2.00 BYK Phase BCetyl Alcohol (and) Glyceryl Stearate (and) Emulium Delta 5.00Gattefosse PEG-75 Stearate (and) Ceteth-20 (and) Steareth-20 C10-18Triglycerides Lipocire A Pellets 2.00 Gattefosse Ozokerite Kahlwax 18992.00 Kahl Glyceryl Behenate Compritol 888 CG 2.00 Gattefosse PastillesButylene Glycol Cocoate Cocoate BG 4.00 Gattefosse Phase C Effectpigment 5.00 from example 8 Phenoxyethanol (and) Piroctone OlamineNipaguard PO5 0.50 Clariant Glycine Soja (Soybean) Oil, DicaprylylEther, Follicusan DP 3.00 CLR Berlin Magnolia Grandiflora Bark Extract,Lauryl Alcohol Water, Hydrolyzed Corn Starch, Beta Vulgaris DayMoist CLR1.00 CLR Berlin (Beet) Root Extract Linoleic Acid (and) Linolenic AcidVitamin F forte 0.50 CLR Berlin

The effect pigment from example 8 can be used within a range from 1.0%to 10.0% by weight, based on the total weight of the mascaraformulation. Compensation to 100% by weight of the formulation can beeffected with the water from phase A.

Phase A was stirred under high shear. Phase B was weighed outseparately. Phase A and phase B were heated separately to 85° C., thenphase B was added to phase A. Subsequently, phase AB was cooled to 45°C. and, during the cooling, phase C was added gradually while stirring.

Application Example 6: Hair Gel

% by Manufacturer/ INCI name Product name wt. supplier Phase A SodiumMagnesium Silicate (nano) Laponite XLG 2.00 BYK Aqua Water 94.80 Phase BEffect pigment 0.10 from example 6 Citric Acid (and) Water Citric Acid(1 0%) 0.30 Glycerin, Water, Avena Strigosa Seed Extract, Aquarich 1.50Rahn AG Lecithin, Potassium Sorbate, Citric Acid Fragrance Lychee &Grape 0.10 Bell Europe Methylisothiazolinone (and) Phenethyl AlcoholOptiphen MIT 1.20 Ashland (and) PPG-2-Methyl Ether Plus

The effect pigment from example 6 can be used within a range from 0.01%to 2.0% by weight, based on the total weight of the hair gelformulation. Compensation to 100% by weight of the formulation can beeffected with water.

The Laponite XLG was stirred with water until phase A became clear. Thenthe effect pigment from example 6 was added to phase B while stirring.Subsequently, the rest of the ingredients of phase B were addedgradually.

Application Example 7: Body Powder

INCI name % by Manufacturer/ Phase A Product name wt. supplier SyntheticFluorphlogopite Synafil S 1050 40.00 Eckart Polypropylene Synafil W 12348.00 Eckart Bentonite Optigel CK-PC 10.00 BYK Talc Talc Powder 18.00 VWRMagnesium Stearate Magnesium Stearate 4.00 Applichem Effect pigment from20.00 example 5

The effect pigment from example 5 can be used within a range from 0.2%to 5.0% by weight, based on the total weight of the body powderformulation. Compensation to 100% by weight of the formulation can beeffected with Synafil S 1050.

Phase A was mixed and then the powder was dispensed into a suitablevessel.

Application Example 8: Lipgloss

% by Manufacturer/ INCI name Product name wt. supplier Phase AHydrogenated Polyisobutene Versagel 75.30 Penreco (and)Ethylene/Propylene/ ME 750 Styrene Copolymer (and)Butylene/Ethylene/Styrene Copolymer Simmondsia Chinensis Jojoba Oil -2.00 BioChemica (Jojoba) Seed Oil Natural Caprylyl Trimethicone Silcare7.00 Clariant Silicone 31M50 Stearyl Dimethicone Silcare 3.20 ClariantSilicone 41M65 Hydrogenated Polydecene Dekanex 4.00 IMCD 2004 FGIsopropyl Myristate Isopropyl 4.50 VWR Myristate Phase B Effect pigment4.00 from example 6

The effect pigment from example 6 can be used within a range from 0.10%to 8.00% by weight, based on the total weight of the lipglossformulation. Compensation to 100% by weight of the formulation can beeffected with Versagel ME 750.

Phase A was heated to 85° C., then the pigment from example 6 was addedto phase B and stirred until the consistency was homogeneous, and thendispensed into a lipgloss vessel.

Application Example 9: Lipstick

% by Manufacturer/ INCI name Product name wt. supplier Phase AOctyldodecanol Eutanol G 42.5 BASF Candelilla Cera Kahlwax 2039 6.00Kahl Copernicia Cerifera (Carnauba) Wax Kahlwax 2442 6.00 KahlBis-Diglyceryl Polyacyladipate-2 Softisan 649 10.00 Sasol PolyisobuteneRewopal PIB 1000 10.00 Evonik Hydrogenated Polydecene Silkflo 364 NFPolydecene 5.00 Ineos C10-18 Triglycerides Lipocire A Pellets 5.00Gattefosse Acacia Decurrens/Jojoba/Sunflower Hydracire S 5.00 GattefosseSeed Wax/Polyglyceryl-3 Esters Tocopheryl Acetate dl-alpha-Tocopheryl0.50 IMCD Phase B Effect pigment from 10.00 example 10

The effect pigment from example 10 can be used within a range from 0.5%to 20.0% by weight, based on the total weight of the lipstickformulation. Compensation to 100% by weight of the formulation can beeffected with Eutanol G.

Phase A was heated to 85° C., then phase B was added to phase A andmixed. Subsequently, this mixture was dispensed into a lipstick mold ata temperature of 75° C.

Application Example 10: Liquid Eyelid Liner

% by Manufacturer/ INCI name Product name wt. supplier Phase A AquaWater 56.90 Bentonite (and) Xanthan Gum Optigel WX-PC 1.40 Phase BLecithin Emulmetik 100 0.10 Lucas Meyer Copernicia Cerifera Cera Kahlwax2442 1.00 Kahl Stearic Acid Stearic Acid 3.50 Lipo ChemicalsHydrogenated Polyisobutene Panalane L14 5.00 Ineos E Polysorbate 60Mulsifan CPS 1.50 Zschimmer & 60 Schwarz Phase C Effect pigment 4.00from example 2 Polyurethane-35 Baycusan C 18.00 Bayer Cosmetics 1004Aqua and CI 77499 and Methylpropanediol and WorléeBase 8.00 WorléeAmmonium Acrylates Copolymer and AQ 77499/1 Simethicone and CaprylylGlycol and Phenylpropanol Sodium Acrylates Copolymer Phenoxyethanol,Ethylhexylglycerin Euxyl PE 9010 0.60 Schülke & Mayr

The effect pigment from example 2 can be used within a range from 0.5%to 8.0% by weight, based on the total weight of the eyelid linerformulation. Compensation to 100% by weight of the formulation can beeffected with water.

Optigel WX-PC was dispersed in water of phase A and stirred for 10minutes. Phase A and phase B were heated separately to 80° C.Thereafter, phase B was added gradually to phase A while stirring. Aftercooling to 45° C., the ingredients of phase C were added gradually andthe mixture was dispensed into a suitable package.

Application Example 11: Mousse

% by Manufacturer/ INCI name Product name wt. supplier Phase ACyclopentasiloxane Xiameter PMX-0245 8.60 Dow Corning CyclosiloxaneHydrogenated Polyisobutene MC 30 4.00 Sophim Dimethicone (and)Dimethicone Dow Corning 9041 37.14 Dow Corning Crosspolymer SiliconeElastomer Blend Squalane Squalane 5.74 Impag Isononyl IsononanoateDermol 99 10.16 Akzo International Hydrogenated Jojoba Oil Jojoba ButterLM 2.15 Desert Whale Hydrogenated Jojaba Oi Jojoba Butter HM 1.00 DesertWhale C30-45 Alkyl Methicone (and) C30- Dow Corning AMS-C30 1.15 DowCorning 45 Olefin Cosmetic Wax Stearyl Dimethicone Dow Corning 2503 0.47Dow Corning Cosmetic Wax Cyclopentasiloxane (and) Dow Corning 670 Fluid5.00 Dow Corning Polypropylsilsesquioxane Phase B Dimethicone/VinylDimethicone Dow Corning 9506 16.02 Dow Corning Crosspolymer PowderSilica Dimethyl Silylate Covasilic 15 0.17 LCW Talc Talc Powder 5.00Sigma-Aldrich Effect pigment from 3.00 example 4 Phase D Phenoxyethanol,Ethylhexylglycerin Euxyl PE 9010 0.40 Schülke & Mayr

The effect pigment from example 4 can be used within a range from 0.1%to 8.0% by weight, based on the total weight of the mousse formulation.Compensation to 100% by weight of the formulation can be effected withDow Corning 9041 Elastomer.

Phase A was mixed and heated until everything had melted. Phase B wasweighed out separately and mixed with a high-speed mixer at 2400 rpm for60 s. Half of the molten phase A was added to phase B and the mixturewas mixed again in the mixer at 2400 rpm for 30 s. Subsequently, theremaining portion of phase B was likewise added to phase A and themixture was mixed again at 2400 rpm for 30 s. Lastly, phase C was addedto phase AB and the mixture was mixed again in the high-speed mixer at2400 rpm for 30 s.

Application Example 12: Nail Varnish

% by Manufacturer/ INCI name Product name wt. supplier Phase A Effectpigment 4.00 from example 6 Phase B Butylacetat (and) International96.00 International Ethylacetat (and) Lacquers Lacquers Nitrocellulose(and) Nailpolish Isopropyl Alcohol Base 15244

The effect pigment from example 6 can be used within a range from 0.1%to 8.0% by weight, based on the total weight of the nail varnishformulation. Compensation to 100% by weight of the formulation can beeffected with International Lacquers Nailpolish.

Phase A and phase B were mixed and then dispensed into an appropriatecontainer.

Application Example 13: Nail Varnish with Soft-Touch Effect

% by Manufacturer/ INCI name Product name wt. supplier Phase A Effectpigment 4.00 from example 10 Polypropylene Synafil W 1234 5.00 EckartPhase B Butylacetat (and) International 91.00 International Ethylacetat(and) Lacquers Lacquers Nitrocellulose (and) Nailpolish IsopropylAlcohol Base 15244

The effect pigment from example 10 can be used within a range from 0.1%to 8.0% by weight, based on the total weight of the nail varnishformulation. Compensation to 100% by weight of the formulation can beeffected with International Lacquers Nailpolish.

Phase A was mixed and added to phase B, and then the nail varnish wasdispensed into an appropriate container.

Application Example 14: Aqueous Nail Varnish

The effect pigments from examples 1 to 8 and from example 10 can be usedin an aqueous nail varnish according to WO 2007/115675 A2 example 1. Thepigmentation level here is 0.1% to 10.0% by weight, based on the totalweight of the formulation.

Application Example 15: Liquid Eyeshadow

% by Manufacturer/ INCI name Product name wt. supplier Phase A WaterAqua 73.80 Glycerin Glycerin 3.00 H. Erhard Wagner Phase B PEG-800Polyglycol 35000 S 0.60 Clariant Ammonium Aristoflex AVC 0.80 ClariantAcryloyldimehtyltaurate/ VP Copolymer Acrylates Copolymer WorleeMicromer CEK 20/50 5.00 Worlee Phase C Effect pigment from example 310.00 Divinyldimethicone/ Dow Corning HMW 2220 Non- 6.00 Dow CorningDimethicone Ionic Emulsion Copolymer C12-C13 Pareth-3, C12-C13 Pareth-23Phenoxyethanol, Euxyl PE9010 0.80 Schülke & Mayr Ethylhexylglycerin

The effect pigment from example 3 can be used within a range from 0.10%to 20.00% by weight, based on the total weight of the eyeshadowformulation. Compensation to 100% by weight of the formulation can beeffected with water.

Phase A was stirred, then the ingredients of phase B were addedindividually to phase A and stirred until the consistency washomogeneous. Thereafter, the ingredients of phase C were addedindividually to phase AB and the mixture was stirred until theconsistency was homogeneous.

FIG. 1: Scanning electron micrograph of a transverse section of aneffect pigment of the invention in 50 000-fold magnification (based onPolaroid 545).

FIG. 2: Scanning electron micrograph of a transverse section of aneffect pigment of the invention in 50 000-fold magnification (based onPolaroid 545).

FIG. 3: Scanning electron micrograph of a transverse section of aneffect pigment of the invention in 20 000-fold magnification (based onPolaroid 545).

FIG. 4: Detail of the scanning electron micrograph of a transversesection from FIG. 2 with a baseline drawn in at the interface ofnonmetallic substrate in platelet form—coating, and lines arranged atright angles to the baseline. “x” marks the points of intersection atthe interfaces.

FIG. 5: Scanning electron micrograph of a transverse section of thetitanium dioxide-coated pearlescent pigment SYMIC C261 (from ECKARTGmbH) in 20 000-fold magnification (based on Polaroid 545).

FIG. 6: Schematic diagram of the spacer layer.

FIG. 7: Schematic diagram of the position of the spacer layer.

FIG. 8: Concentration profile (line scan) using a transverse section ina scanning electron microscope with energy-dispersive microanalyzer(EDX) of example 12 prior to calcination.

FIG. 9: Concentration profile (line scan) using a transverse section ina scanning electron microscope with energy-dispersive microanalyzer(EDX) of example 12 after calcination.

The invention claimed is:
 1. An absorbent effect pigment comprising anonmetallic substrate in platelet form and a coating applied to thesubstrate, wherein the coating comprises a) optionally a layer 1comprising or consisting of at least one of tin oxide, tin hydroxide ortin oxide hydrate, b) a layer 2 having a high refractive index n>1.8,the layer 2 comprising at least one of metal oxide, metal hydroxide ormetal oxide hydrate, and c) a layer 3 having a high refractive indexn>1.8, the layer 3 comprising at least one of metal oxide, metalhydroxide or metal oxide hydrate, at least one of layers 2 and 3comprises at least two different metal ions and layers 2 and 3 areinterrupted by a spacer layer, wherein the at least one spacer layercomprises connections and cavities.
 2. The absorbent effect pigment asclaimed in claim 1, wherein the nonmetallic substrate in platelet formis selected from the group consisting of natural mica platelets,synthetic mica platelets, iron mica, glass platelets, SiO₂ platelets,Al₂O₃ platelets, kaolin platelets, talc platelets, bismuth oxychlorideplatelets and mixtures thereof, and the nonmetallic substrate inplatelet form has optionally been coated with at least one of metaloxide, metal hydroxide or metal oxide hydrate.
 3. The absorbent effectpigment as claimed in claim 1, wherein the effect pigment comprisesfurther layers of high and/or low refractive index and optionally atleast one further spacer layer.
 4. The absorbent effect pigment asclaimed in claim 1, wherein the at least two different metal ions oflayers 2 and 3 are selected from the group of metals consisting of Ti,Fe, Sn, Mn, Zr, Ca, Sr, Ba, Ni, Sb, Ag, Zn, Cu, Ce, Cr and Co, andwherein the proportion of noncoloring metal ions selected from the groupof the metals consisting of Ti, Sn, Zr, Ca, Sr, Ba and Zn totals ≤40% byweight, and the proportion of coloring metal ions selected from thegroup of the metals consisting of Fe, Ti, Sn, Mn, Ni, Sb, Ag, Cu, Ce, Crand Co totals ≥4% by weight, determined by means of XRF in each case,calculated in each case as the elemental metal and based in each case onthe total weight of the absorbent effect pigment of the invention. 5.The absorbent effect pigment as claimed in claim 1, wherein a weightratio, determined by means of XRF and calculated as the elemental metal,of noncoloring metal ions to coloring metal ions in the absorbent effectpigment of the invention is <20.
 6. The absorbent effect pigment asclaimed in claim 1, wherein the at least one spacer layer is arrangedessentially parallel to the surface of the nonmetallic substrate inplatelet form.
 7. The absorbent effect pigment as claimed in claim 1,wherein the at least one spacer layer has a mean height h_(a) from arange from 5 nm to 120 nm.
 8. The absorbent effect pigment as claimed inclaim 1, wherein the at least one spacer layer has a network density of<85%.
 9. An absorbent effect pigment comprising a nonmetallic substratein platelet form and a coating applied to the substrate, wherein thecoating comprises a) optionally a layer 1 comprising or consisting of atleast one of tin oxide, tin hydroxide or tin oxide hydrate, b) a layer 2having a high refractive index n>1.8, the layer comprising at least oneof metal oxide, metal hydroxide or metal oxide hydrate, and c) a layer 3having a high refractive index n>1.8, the layer comprising at least oneof metal oxide, metal hydroxide or metal oxide hydrate, at least one oflayers 2 and 3 comprises at least two different metal ions and layers 2and 3 are interrupted by a spacer layer, wherein the at least one spacerlayer comprises connections and cavities, and wherein the spacer layerhas a standard deviation of the relative height of σh_(Rma) in a rangeof 0.2 to 18%, wherein the relative height h_(Rma) is defined as theratio of the height h_(ma) to the layer thickness of the overall coatingand h_(ma) refers to the sum total of the layer thickness of optionallayer 1, layer 2 and half the height h_(a) of the spacer layer.
 10. Theabsorbent effect pigment according to claim 9, wherein the mean heightof the spacer layer h_(a) is determined by the following method: theeffect pigments are applied in a lacquer and cross sections are preparedand scanning electron micrographs analyzed thereof comprising the steps:establishing the upper and lower substrate surfaces as baselines whichare the longer side of the nonmetallic substrate in platelet form ineach case and drawing the baselines onto the scanning electronmicrograph of the transverse section; analyzing the scanning electronmicrographs of the transverse sections with the aid of the AxioVision4.6.3 image processing software (from Zeiss); drawing a sufficientnumber of parallel lines at 50 nm intervals at a 90° angle with respectto the upper and lower baselines corresponding to the two surfaces ofthe substrate in platelet form establishing a grid over the effectpigment shown in the scanning electron micrograph of a transversesection (FIG. 4) using a magnification of at least 50,000-fold, based onPolaroid 545 (4″×5″); proceeding from the respective baseline of thenonmetallic substrate in platelet form, in the direction of therespective outer layer 3 or the respective outermost layer, the pointsof intersection between the parallel lines arranged at right angles tothe respective baseline with the respective interfaces of the optionallayer 1 with layer 2, of layer 2 with the spacer layer, of the spacerlayer with layer 3, and of layer 3 with the environment or with anyfurther layer applied are analyzed manually, wherein in the case thatone of the lines drawn at 50 nm intervals occurs directly above aconnection point or a spacer only the respective point of intersectionof the line at the interface of layer 3 with the environment or with anyfurther layer applied is recorded; and determining the layer thicknessesof layers 2 and 3, the layer thickness of the overall coating, the layerthickness of further layers optionally present, and the height h_(a) ofthe spacer layer by formation of differences, wherein the layerthickness of layer 2 is calculated from the difference between therespective measured points of intersection at the respective interfacesof layer 2 with the spacer layer and of either optional layer 1 withlayer 2 or the baseline with layer 2 if the nonmetallic substrate inplatelet form has not been covered with further layers beforehand, andthe layer thickness of layer 3 is calculated from the difference betweenthe respective measured points of intersection of layer 3 with theenvironment or any further layer applied and of the spacer layer withlayer 3 and the height h_(a) of the spacer layer is calculated from thedifference between the respective measured point of intersection ofspacer layer with layer 3 and layer 2 with the spacer layer, wherein theheight h_(a) is determined by forming the arithmetic mean by conductingthis procedure to at least 100 of the parallel lines arranged at rightangles to the baselines.
 11. The absorbent effect pigment according toclaim 9, wherein the relative height of σh_(Rma) in a range of 0.3 to15%.
 12. The absorbent effect pigment according to claim 9, wherein thenonmetallic substrate in platelet form is selected from the groupconsisting of natural mica platelets, synthetic mica platelets, ironmica, glass platelets, SiO₂ platelets, Al₂O₃ platelets, kaolinplatelets, talc platelets, bismuth oxychloride platelets and mixturesthereof, and the nonmetallic substrate in platelet form has optionallybeen coated with at least one of metal oxide, metal hydroxide or metaloxide hydrate.
 13. The absorbent effect pigment according to claim 9,wherein the effect pigment comprises further layers of high and/or lowrefractive index and optionally at least one further spacer layer. 14.The absorbent effect pigment according to claim 9, wherein the at leasttwo different metal ions of layers 2 and 3 are selected from the groupof metals consisting of Ti, Fe, Sn, Mn, Zr, Ca, Sr, Ba, Ni, Sb, Ag, Zn,Cu, Ce, Cr and Co, and wherein the proportion of noncoloring metal ionsselected from the group of the metals consisting of Ti, Sn, Zr, Ca, Sr,Ba and Zn totals ≤40% by weight, and the proportion of coloring metalions selected from the group of the metals consisting of Fe, Ti, Sn, Mn,Ni, Sb, Ag, Cu, Ce, Cr and Co totals ≥4% by weight, determined by meansof XRF in each case, calculated in each case as the elemental metal andbased in each case on the total weight of the absorbent effect pigmentof the invention.
 15. The absorbent effect pigment according to claim 9,wherein a weight ratio, determined by means of XRF and calculated as theelemental metal, of noncoloring metal ions to coloring metal ions in theabsorbent effect pigment of the invention is <20.
 16. The absorbenteffect pigment according to claim 9, wherein the at least one spacerlayer is arranged essentially parallel to the surface of the nonmetallicsubstrate in platelet form.
 17. The absorbent effect pigment accordingto claim 9, wherein the at least one spacer layer has a mean heighth_(a) from a range from 5 nm to 120 nm.
 18. An absorbent effect pigmentcomprising a nonmetallic substrate in platelet form and a coatingapplied to the substrate, wherein the coating comprises a) optionally alayer 1 comprising or consisting of at least one of tin oxide, tinhydroxide or tin oxide hydrate, b) a layer 2 having a high-refractiveindex n>1.8 the layer 2 comprising at least one of metal oxide, metalhydroxide or metal oxide hydrate, and c) a layer 3 having ahigh-refractive index n>1.8, the layer 3 comprising at least one ofmetal oxide, metal hydroxide or metal oxide hydrate, at least one oflayers 2 and 3 comprises at least two different metal ions and layers 2and 3 are interrupted by a spacer layer, wherein the spacer layercomprises connections and cavities and wherein the spacer layercomprises an area proportion of cavities from a range of 51% 99%,measured from scanning electron micrographs of traverse sections. 19.The absorbent effect pigment according to claim 18, wherein the areaproportion of cavities is a range of 63% to 96%.
 20. The absorbenteffect pigment according to claim 18, wherein the nonmetallic substratein platelet form is selected from the group consisting of natural micaplatelets, synthetic mica platelets, iron mica, glass platelets, SiO₂platelets, Al₂O₃ platelets, kaolin platelets, talc platelets, bismuthoxychloride platelets and mixtures thereof, and the nonmetallicsubstrate in platelet form has optionally been coated with at least oneof metal oxide, metal hydroxide or metal oxide hydrate.
 21. Theabsorbent effect pigment according to claim 18, wherein the effectpigment comprises further layers of high and/or low refractive index andoptionally at least one further spacer layer.
 22. The absorbent effectpigment according to claim 18, wherein the at least two different metalions of layers 2 and 3 are selected from the group of metals consistingof Ti, Fe, Sn, Mn, Zr, Ca, Sr, Ba, Ni, Sb, Ag, Zn, Cu, Ce, Cr and Co,and wherein the proportion of noncoloring metal ions selected from thegroup of the metals consisting of Ti, Sn, Zr, Ca, Sr, Ba and Zn totals≤40% by weight, and the proportion of coloring metal ions selected fromthe group of the metals consisting of Fe, Ti, Sn, Mn, Ni, Sb, Ag, Cu,Ce, Cr and Co totals ≥4% by weight, determined by means of XRF in eachcase, calculated in each case as the elemental metal and based in eachcase on the total weight of the absorbent effect pigment of theinvention.
 23. The absorbent effect pigment according to claim 18,wherein a weight ratio, determined by means of XRF and calculated as theelemental metal, of noncoloring metal ions to coloring metal ions in theabsorbent effect pigment of the invention is <20.
 24. The absorbenteffect pigment according to claim 18, wherein the at least one spacerlayer is arranged essentially parallel to the surface of the nonmetallicsubstrate in platelet form.
 25. The absorbent effect pigment accordingto claim 18, wherein the at least one spacer layer has a mean heighth_(a) from a range from 5 nm to 120 nm.
 26. A process for producing theabsorbent effect pigment as claimed in claim 1, wherein the processcomprises: (i) optionally applying an uncalcined layer comprising orconsisting of at least one of tin oxide, tin hydroxide or tin oxidehydrate to the nonmetallic substrate in platelet form, (ii) sequentiallyapplying three uncalcined layers A, B and C each consisting of orcomprising at least one of metal oxide, metal hydroxide or metal oxidehydrate, where the layers A, B and C are arranged directly one on top ofanother and where the at least one metal oxide, metal hydroxide and/ormetal oxide hydrate applied in the layer B, in relation to the metalion, is different than the metal ion(s) of the metal oxides, metalhydroxides and/or metal oxide hydrates of layer A and layer C, (iii)calcining the product obtained in step (ii) at a temperature from arange from 400° C. to 1000° C. to obtain the absorbent effect pigmentcomprising at least one spacer layer.
 27. The process as claimed inclaim 26, wherein the metal ions present in layer B diffuse at leastpartly into layer A and/or layer C to form the at least one spacer layerin the calcined effect pigment.
 28. The process as claimed in claim 26,wherein the two or three sequentially applied metal oxides, metalhydroxides and/or metal oxide hydrates for production of the layers Band C or the layers A, B and C do not comprise any metal ion selectedfrom the group of the metals consisting of Si, Mg and Al.
 29. A processfor producing the absorbent effect pigment as claimed in claim 1,wherein the process comprises: (i) sequentially applying two uncalcinedlayers B and C each consisting of or comprising at least one of metaloxide, metal hydroxide or metal oxide hydrate to a calcined, singly ormultiply coated nonmetallic substrate, where the layers B and C arearranged directly one on top of another and where the at least one metaloxide, metal hydroxide and/or metal oxide hydrate applied in the layerB, in relation to the metal ion, is different than the metal ion(s) ofthe metal oxide, metal hydroxide and/or metal oxide hydrate of layer Cand of the layer which directly adjoins layer B in the substratedirection, (ii) calcining the product obtained in step (i) at atemperature from a range from 400° C. to 1000° C. to obtain theabsorbent effect pigment comprising at least one spacer layer.
 30. Themethod according to claim 29, wherein the metal ions present in layer Bdiffuse at least partly into layer A and/or layer C to form the at leastone spacer layer in the calcined effect pigment.
 31. A process forproducing a pigmented cosmetic formulation, plastic, film, textile,ceramic material, glass, paint, printing ink, writing ink, varnish,powder coating or a material for a functional application comprisingintroducing the absorbent effect pigment of claim 1 into a cosmeticformulation, plastic, film, textile, ceramic material, glass, paint,printing ink, writing ink, varnish, powder coating or a material for afunctional application.
 32. The process according to claim 31, whereinthe functional application is laser marking, IR reflection, orphotocatalysis.
 33. An article comprising at least one absorbent effectpigment as claimed in claim 1.